Hi Chris and Bo,
Such peeling of paint on wheel covers is not uncommon. When the aeroplane was built it would have been painted in P.C.10 which is technically a pigmented dope rather than a paint, but it has almost certainly been finished with paint when it was restored, as is the case in most restorations. I don't know if you are aware Bo but P.C.10 was actually applied over clear doped linen. The CDL on this aeroplane is very yellow. This could be a result of the yellowing of the varnish with age. Jacek has informed us that the aeroplane was donated to the museum in 1964 and subsequently restored, so it might have yellowed with age if the restoration was carried out in the 1960's or 1970's. More commonly, however CDL is restored as yellow or yellowish due to the fact that pieces of CDL used for reference have yellowed with age. It took a lot of searching but I was eventually able to find a piece of CDL which had been relatively well protected, and it is an off white colour. This confirmed what I had suspected, which is that the yellow colour of the undersides is due to ageing and weathering. The correct colour for CDL is an off white colour, similar to cream. TVAL have done an excellent job with their research, and their colours are very accurate. I'm sure you've seen plenty of photos and video clips of TVAL aeroplanes, thanks to James! I've certainly been enjoying a lot of videos of TVAL aeroplanes here since I joined a few days ago.
I hope this is helpful.
Regards,
David.