They are great guns. Just stay away from the magnum ones which are harder to shoot accurately.
I would shoot it as is over a chrony and if you wanted to, release some air in the gas ram but buy a
pump for it so you can get it back to spec when you want to. Very easy to shoot with less air in them.
You would have to surf some UK websites and get a used one, they can still be bought in the $700-$1300 price range plus international shipping. Do a search for gunstaruk for starters then you can google Theoben SLR98 for sale that ought to get you pointed in the right direction. Be advised that you need to do a conversion into US Dollars to calculate the cost plus add international shipping.
CA