Simply look at what competitions the club caters for and apply for a firearm in each calibre. I would think about a 38/357 funderlever rather than a 45 long colt, its a lot cheaper to feed in 38 special. Apply for a .22 rifle, a .303 and a 308 and there you have the basis for building up a good set of firearms in your first 5 years.
It may also help if the club has a shop where club guns come and go, this way you can usually sell beginner rifles a year or two later to move onto newer rifles!
Some RFDs will take back rifles for close on what you payed if you are buying its replacement from them. Also consider other calibres such as 8mm mauser, lots of good used rifles about and lots of quality ammo from PPU.
38/357 is a great choice, especially if you get into shooting what passes for a revolver in the UK these days.
Cheap bullets, frugal on propellant & the brass lasts forever (I shoot it a lot in the US & some cases must be on their 20th or more load by now).
I like a pistol grip stock, so sod the traditional looks, I'd go for one of these.
In 1966 I attend a rifle match against 26 Medium Rgt (RA) at Shoeburry Ness. Part of the competition was falling plates. We had never done that before, so our hosts went first although I don't recall what they were firing. We had M-1 Garands and I don't know how that happened because they were no longer standard AF issue.
at the command commence firing, we did. And every now and again a plate would fall over. WTF? Cease fire. We went forward and found a number of the plates still standing had nice, shiny, .30 holes through them.
The ammo had been scrounged from somewhere. It was belted and mostly black tipped AP ball.