Thanks for everybody's help. We have a Reno garage not far away and so I will pop in and see if they can get hold of some new ones. If not I will look at the other options. App the rims of the wheels are corroded and the air is leaking out of they tyres. The man at the garage said that nothing can be done, but I have just read a post about possibly grinding the bad part away, but will try and get some new ones first,
Will keep you updated, thanks.