Welcome to STB mate - and good luck with your HFT ambitions. It's a great sport.
Most targets are "free choice" - you can take these prone, kneeling or standing.
I believe you are allowed to take the "prone only" shots kneeling or standing, if there is a good reason for doing so. I expect one of the longer-standing shooters will be along soon hopefully to confirm this.
Looking forward to meeting you on the circuit before too long.
Weihrauch HW100KT .177
Weihrauch HW98 V-Mach .177
Weihrauch HW80K .22
Weihrauch HW77K .177
Weihrauch HW45 "Silver Star" .177
Weihrauch HW35 .177
Daystate Mk.4 Panther .177
Air Arms FTP900 .177
Glevum Target & Sports Club, Gloucester.
Parkstone Gun Club, Poole