If you're not a member but want to give the gym a try, there is a computer outside where you can buy a day pass immediately. Make sure you keep an eye on your stuff though!
Cheap, but a perfect example of getting what you pay for. Namely, a long wait for the equipment you want to use, or someone standing on your head to rush you
Don't bother with free weights between 1730 and 2100. You need a lock! Don't buy their £ 3 locks, instead bring your own! Only one squat rack! Only one bench press! Nice location.