Parkside also do the 2 singlke jabs that are available.
http://www.parkside-hospital.co.uk/
I agree with the previous poster. For me it's not so much about the general links, but about knowing your child and their health. It's not a great idea to overload them if they have something else going on that's using up a lot of their immune activity .... allergies, viruses, even colds.
In the end though, we waited for a good time for our child (health-wise) and did do the MMR, as our consultant said one big thing to trigger the immune system wasnt really all that different to having to keep doing separate jabs and keep heightening it over and over.
I think it's fine to wait a little, for a time when your child is bigger / stronger & their little system is a little more settled. We'd have waited even longer had the Measles scare not occurred soon after her first birthday anyway.