Rasmus – Thanks for the info, got some info from Jonas as well (thanks) and the different bolt diameters are 114.3 up to 1987 and 108 from 1988 onwards. I went and picked up some new bolts today and they are 14 x 1,5 and will work on steel and alloy wheels. I was told there was only one angle for this type of bolt, presumably 60 degrees.
After having a good look at all the writing on the wheels it turns out one of the wheels is a 6J x 15 and the other three are 5 1/2 J x 15. Also major problems getting the wheel nuts loose, so far one has snapped off, hopefully I will be able to drill and tap the rest of it out. The strangest thing is the cone/tappered part of some of the bolts is deformed. How that’s happened I don’t know. Will post an image once I have got all the wheels off.
Now to find a replacement rim.
Thanks – Gary