Is it heads, or heads+helmets, that you're after?
Do you know anyone who has any Wargames Factory British Firing Line from their Zulu War range?
They might serve - lose heads with no hats (some bearded, some with moustachios) that you could maybe sculpt hoods, caps or helmets on. You get something like 28 heads in a box of 20 troops, so almost anyone with Wargames Factory British should have some spare heads (of those 28, 8 are moulded wearing Glengarry caps and 20 are 'bare', to be given pith helmets, so it's possible to use up all the useful heads making a unit of guys with pith helmets).