Mick,
You can change the tyres over. It's a bit of a job getting the rim out of the runflats, and the insert is also a pain to get out. I use a couple of long bars to pry everything apart. You can use the same tubes and flaps, but for £10 each I suggest you put in new tubes. You can get these from ATS, they're the same as many tractor front tyres. I inflate my tyres to 40psi front and 45 rear.
Chris