thanks for the responses.
Struggled to find anything via local breakers' yards and, given time restraints as I need to have my MOT retest, I've gone the budget alloys/tyres route via Halfords - £349.99 all in. Bit 'prettier' than I'd intended, but I'll cope.
Hoping to sell the usable wheels on eBay to recoup some of the costs. Two of the weels have some pot-hole damage but not MOT failure damage; the other two have actually buckled slightly, enough that they're not repairable according to the place I took them to locally. Three of the four tyres are ok.
Was planning on selling my KA but, given the latest spend on it, looks like I have to keep it a while longer!