Meguires vinyl cleaner , and then aerospace 303 as a protectant against sunlight , avoid any silicon products Nb peanut butter also works -it uses the oils in the butter !! but needs to be pretty clean first
If you are handy at glueing and sticking (blue peter style ) you can simply recover with new vinyl - it is as cheap as chips!! Not for everyone though as some people seem to have disaster awaiting when DIY calls !!
The boot polish worked a treat Phil! I found liquid polish worked best. My dash top needed three coats with each one being allowed to dry before appling the next. Polished with a soft cloth and it came up like new.