I just moved to the area and needed a tanning salon, I'd had a good experience with the same chain in London Bridge so I bought a long course of stand-up tanning minutes at the Liverpool St station branch expecting the same level of service. What a mistake. My two main problems with this branch are:
1. Staff. They really couldn't care less. They would have to try very hard to give a worse service to customers. Facebook, their phones and chatting with each other seem much more important than their customers who are frankly an annoyance to them. It would usually take them a good 10-15 seconds to look up from their phones when I walked in and stood at the front desk less than a foot away from them. Several times the front desk was unmanned while one staff member was giving another some kind of beauty treatment in one of the side rooms.
2. Tanning booths. There are about 8 or 9 and I think I used all of them at some stage. They all have dead bulbs, some had as many as six (out of 24). I can forgive one or two dead bulbs if it happened occasionally and was fixed promptly (never the case). I would always tell the staff if the bulbs were dead and to their credit they would sometimes offer to add back a few minutes to my account (although when I went back subsequently they hadn't once added any minuted back). A more cynical person would suggest they actively 'forgot' to refund the minutes in the hope that the customer would forget by the time they returned. In reality I suspect the staff are simply too lazy to bother.
If you need a tanning salon near Liverpool Street I would suggest looking elsewhere.