offered to spray a bonnet for a mate and it is already sprayed up in two pack primer.will the cellulose top coats affect the primer.Any advice on the technique of spraying cellulose to get a good finish would be appreciated.

cue anyone else but I am pretty sure the celly paint will have no effect on the two-pack. once two-pack has gone off it's pretty chemically inert and tough.

I thought that celly was not available to buy after 1 jan 2007? (EU enviroregulations)

Trick with cellulose is to spray wet on wet and blow any runs out whilst they are still wet. Let it drip off the edges if needed, and trim once dry.

Cheers

Pete

Celly is still available for non-automotive use IIRC (i.e. industrial and probably agricultural)
The range of colours you can get will probably decrease over the years, but it's still available if you need/want it.