They were appearing mysteriously and randomly, looking like scratches on my scalp. No idea how they got there or why.
I discovered this morning my shaver foil has a tiny hole in it.
I've owned this shaver since 2006, and this is the second time the foil has needed replacing. The previous shaver was from Remington, and not only did it leave razor burn all over me, but the foils wore out in less than 12 months and cost 75% of the purchase price of the shaver, and the batteries were failing after 2 years. Junk.
It looks like Amazon have the correct parts, as do shavers.co.uk. Glad they're still made, even though they're >1/2 the original cost.
Parts ordered, including a 100ml bottle of Wahl lubricating oil for £2.60 - a bit better than the 5ml bottle supplied by Braun originally and used very occasionally to conserve supplies. This should last quite a while and hopefully reduce wear significantly.