Ritz is a very small music shop in Putney. They sell a variety of instruments and it was where I got my 3 student violins from and i also know you can do instrument rentals, for a good price! They sell music books for all instruments and I have often heard the sounds of electric guitars and drum kits from upstairs but I have never dared to venture up the narrow staircase!
The staff are helpful and knowledgeable, and the only problem I have had in there was when a friend was ordering a violin case, they didnt have one so she waited a couple of weeks and they still hadnt ordered it and then she went in again and then they had one but in the totoally wrong colour. It’s nothing big, but the sort of hassle that you just wished you ahd gone elsewhere.
After saying that I think overall they are a good music shop and are really helpful. I seem to recall them once fixing a violin bridge for free when it fell off so they come across more as music lovers rather than money lovers which I like.