Hi Dave,
Either the Meguiars Pro Wheel Cleaner @ £8.10 or the P21S Gel Wheel Cleaner kit @ £12.99 are ideal. They are very effective and are both ph neutral so won't harm the wheels in any way no matter how often you use it.
If you want something slightly cheaper the Meguiars Hot Rims is very good @ £6.99. It's only mildly acidic (nothing like Wonder Wheels) but, is still very good at the job.
Any wax or sealant will do fine..... Anything that puts some protection down is a good thing. Sealants will last a bit longer though as they aren't as sensitive to heat that may get built up through the wheel. If you want something specific, Poorboy's do a very good Wheel Sealant for £12.99. Or, go for one of the bodywork sealants as then you can use it everywhere else as well.
Cheers
.