Thanks for reply Micky, I tried a search of MotorWorks and MotoBins, the former doesn't seem to have the correct size, the latter has none. Off to Maroc in a couple of weeks, want to take spares, so looks like the local bmw dealer then...
Try www.tyresalesuk.com have only used them for rim tape before but seem to a have a good selection of tubes.
Tyre prices seem ok as well and was thinking of using them as I need set of tyres and tubes for both my 800 and VanVan.
I just buy them off ebay, Personally I use continental ones as i like that the base of the valve is rubber coated and they come with a good quality metal valve cap