If you want a centre stand it's worth looking at Cosmo Accessories on here for one. Cheaper than Suzuki and gets good reviews.
Heated grips, I have Dr Bike ones (which I was told are Oxford ones rebranded) which cost £30. They are brilliant.
Also worth looking at Cymarc and Ravetech on here too for extra ideas (both get good reviews) and offer things like bash plates, radiator covers etc.
Bigpie on here makes plug and play switched accessory connections so things like heated grips only come on with the ignition, and also headlight relays which can help protect the wiring.
Not an accessory but something I would do is get the tank and airbox housing off and cover all the connectors behind the radiator in ACF50 and then wrap them in old inner tube or something to keep the water out. It'll save you a lot of hassle in the long run.
Finally, Fat Rat has a whole host of goodies in the shop section at the link at the top