Thanks a million for all of your replies.
I think that I have decided that I am going to tackle head on and ask that post Christmas she revert to her previous working arrangement i.e. her and our daughter not her, her husband and our daughter.
I want to be tactful but I do feel uncomfortable and I do think that I should trust my gut. I am having Christmas tea with her so that we can give her her Christmas card and present. I think that I will mention it then and bill as a New Year arrangement.
I really am happy for him to pop in to pick her up at the end of the day but I prefer that is all he does unless we have a prior arrangement.
Thanks again for all of these very thoughtful replies. They have put my mind at rest about saying something.
Merry Christmas everyone.

If you are not happy I would talk to the nanny. But also why not invite them over for a Christmas drink one evening - means you can interrogate him and find out what he does / done.
I would also ask for a dbs if he wants to be in your house and around you children.

Coming from an ex nanny and mother to 2 children this isn't normal I'd have a gentle word with her then if need be put a stop to this situation. Your poor nanny he seems controlling my goodness hasn't he got a job? I wouldn't feel comfortable at all at the end of the day you are paying her not him. This isnt very proffesional it's one thing having nanny play dates but another having the husband tagging along

i dont see what his age alone has got to do with it. but i think you should follow your gut instincts. she shouldnt be having him over during work hours, esp without asking you first. i would just explain that you prefer she only meets with people in the day that is work related- ie playdates etc and you would rather her partner or any friends she has outside of work, not to visit during working hours

I would trust your gut instinct - if you're not comfortable, put a stop to it ASAP.  A DBS certificate doesn't guarantee anything, even if you were to ask him for one.  It's just plain odd that he would want to be with her at work.  She isn't being coerced/controlled by him, is she?

I’d also like to add - who takes their husband to work? It’s not very professional. Whether it’s him collecting and dropping her and your child off somewhere or physically being in your home. That’s not something I’ve ever heard of. Your home is your space. You haven’t allowed him to enter your home, she hasn’t asked prior consent. So many red flags here, what if something gets damaged, lost, stolen not to mention all the safeguarding issues. I would take a look at her contract/ job description.

How worrying for you. Hope this gets sorted.

Ultimately I don’t see this as an age issue but I do see this as an issue. However, I do sympathise as I would be worried too.

To my understanding your child/ children are to be looked after by someone with a DBS. Now, even when child minders have a DBS if there is someone else living at home who may be around the children too at some time or other would then need to have a DBS too.
So, potentially her partner should at least have a DBS if he has access to your children?

I would say follow your gut, mothers know when things are not right, does he have a DBS certificate. you must have guidelines in place with your nannie - have the talk with your daughter about her body and what can and can not be touched by people.

He’s probably trying to engage in the place she works. But its just not the right thing. You treat her like a part of your family but she is still your employee.. so her boyfriend cant come to her workplace. Gently bring it up.

Not sure it’s says great things about your nanny’s judgement to put you in this position

Just to give a slightly different point of view - our nanny has been with us for 6 years and is part of the family. My youngest was born while she was with us. Her and her husband don’t have children of their own but enjoy being with children. Her husband comes with her when she does extra babysitting, or looks after them on the weekend, and he drives her to pick them up from school abs then leaves. So he doesn’t really come into the house in her regular working hours and has a very good relationship with my children. I see it as a bonus as they are getting the attention of another caring adult. BUT she always asks me if it’s ok if he comes into the house, even though I always say yes and this has been the arrangement for some time. I would be very annoyed in your position if I had not been asked, and I would also find it odd if it was in her normal working hours.

Agree with all posts above.
Does he not have a job?

We had a similar issue some years ago with our nanny's boyfriend popping by for lunch a few times a week. We only found out because of ring doorbell. We had words with our nanny about it and it stopped immediately. She didn't take offence and apologised profusely (especially given the element of "deceit" as he had been visiting without our knowledge).

We explained that we didn't have an issue with her socialising as we understood that adult company is nice when you are with small children all day; but that during the working day such socialising should be in the context of something beneficial for our child e.g. a playdate with another nanny / child, visits to playgroups etc. We felt that a visiting adult who might have no interest in children would take away from the attention our child was getting; and potentially raised safeguarding issues.

Hope that helps

As a nanny and a mum I find it odd that your nanny’s partner is hanging out with her at her work place in your absence … It’s probably innocent but it’s not right. please don’t feel bad and have a chat with her. Your daughter is your priorities xxx

Why should you by default trust him?
Do not ignore your gut instinct!

When I was growing up our family friend had a live in nanny whose partner would visit periodically. They later found that the partner sexually abused the child. As I write this it upsets me - the child has gone on to have many challenges in life due to this experience.

Age is not the issue - your motherly gut instinct is!!. You may trust your nanny but she is still your employee, so keep your head on.

Even if the partner has a DBS check - which they should (and our childminder had this for her husband) - do set some rules immediately around her partner’s involvement and set boundaries. Ask for the DBS check initially if you haven’t already. Keep an eye on the situation and your instinct,and if worse comes to worse you should find another nanny. I know this sounds rash but your child’s protection (as you know) is your priority.