Everything you need to achieve a full sized pannier on the left hand side of your 1150:

£80
Prefer not to have to post (particularly if you want the cat) so collection preferred from Welwyn Garden City but I’d guess probably £15 postage.
- RT/RS System pannier, lock removed to enable recoding to your key
- Modified left hand footrest (RT/RS pannier has its forward mount differently aligned to the GS)
- Stubby pipe with clamp
- (optional) Catalytic converter - you wouldn’t want to run a stubby with a y-piece

£80
Prefer not to have to post (particularly if you want the cat) so collection preferred from Welwyn Garden City but I’d guess probably £15 postage.