you could be right gary, the heads on my bike have got bigger valves fitted, pretty well certain that they are 37 exh and 31 inlet. this could mean the heads are 888R items with bigger valves etc, or could mean nothing at all. the part number does not match with ones I've checked against so far.
still looking into cams, pistons etc.
this is all getting just a tad confusing , but I'll get there in the end.
I recently bought some parts for an SP3 from Ducati. For things like the piston rings, head gaskets and shell bearings the system showed the old part numbers superceded by more recent 916 parts and all in stock.
The SP5 barrel is the same as an SP3. I got a pair of used SP5 barrels and pistons for UKP 70 on e-bay a few months ago. Worth keeping an eye out for parts there.