I had a file and polish at Go Glam. Convenient location, good value and excellent quality - stayed chip-free for over a week! Worth noting they only take cash.
Go Glam were very accommodating even though I was 10 minutes late for my appointment. Probably the best acrylic set I have experienced in London (I was seen by Lynn - she is quiet but did an amazing job!).
My only critique would be the fact that you can over hear staff's personal conversations but, it did not ruin my experience.