The windows here are mostly ancient double-glazed uPVC, but not worth replacing as they are still draughtproof and the extra insulation of newer ones probably saves about £10/year.
However, the external sill of the lounge window has lost its fake rosewood effect after 30 years of sun and bird shit (the TV aerial is above!) and is now quite rough, matt, and pale.
There are services that will re-foil the sill but it's just that one part and too small to GAMI. Are there any DIY caps or foils available?