You need to be an owner of a 260 before you can become a member (I'm not commenting on them being the rules ).
You can tell members as their names are green and past owners are purple. Non-owners are blue.
Rover 75 V8
Formerly:
MG ZT-T 260
R75 Conn SE 2.5 V6 Auto Vanden Plas (LWB)
01 '51' Rover 75 2.0 Diesel Conni Auto Tourer // 99 'T' Rover 75 2.5 Conni Auto