Buy a belay plate, a few screwgates, a couple of 120 slings (for cows tail purposes if you do a multi pitch) and some prussik cord (if you need help tying them, ask an older club member to show you how!). Maybe a nut key…
Don’t buy nuts/hexes/cams until you actually have a feel for trad and want to do it. Lots of people join the club and stay as indoor climbers or just sport climbers, so why waste upwards of a £200 on gear that may never get used?
Likelihood is that you will begin climbing with older ones in the club who will have a full rack. Borrow from the club after gaining enough experience/desire to want to trad climb. Eventually you will get to a stage were you want to use your own gear, and by then you will probably have a bit more money to splash out on it… or not!