Thanks everyone for your replies and I agree - what a shame. In the end we went to Balfe's bikes Streatham as they sell Frog bikes (https://balfesbikes.co.uk/our-stores/streatham/). Really good service (thank you!). Just a shame no longer a bike shop on our doorstep.

I can highly recommend London Cycle Workshop on St John's Hill.  I've been using them for years and they will do you a good job for a fair price.  

Windows now painted over, so looks like they're gone for good. What a pity -- very surprising too, as less than a month ago they were advertising for a new bike mechanic to join them.

There is a proposal at Companies House for them to be struck off: https://beta.companieshouse.gov.uk/company/07985628

I hope they re-open, as it was such a friendly and welcoming place, and very conveniently located.

Does anyone know what is going on with Everyone Bikes on Northcote Road? The website says it was due to be closed until the end of September but it's now very much October and no sign of any life. We went by on Saturday and there was a sign on the door, and they're still not answering the phone or responding to emails. It's our son's birthday in a couple of weeks and he is desperate for a new bike... Thank you!