I'm with Arwyn and grumpypa
That'll be exactly what has gone on. There are different size off-set rims and it looks like a set were bought without too much thought to fitment requirements!
You're right in that there is not much adjustment but your car may well have had a mod to dial out the positive camber that older vehicles had as standard. at that time they were setting them in a neutral position from the standard positive camber and this wouldn't help as it would tip the top of the wheel inboard. Have a look at the bottom tube ends of the cross head where the hub is bolted on, you might see the mounting point has been changed. Perhaps the cross head has been replaced (often the subject of accident damage) or the top mount plate has been lengthened, in any event something is amiss as that is wrong but the reason will become apparent with investigation and measuring every thing. I should be able to find some appropriate chassis, crosshead schematics which are age appropriate but the heritage guys at MSCC would be a good starting point, worth joining if you are not yet a member, especially for parts advice and tech knowledge of what the cars should have fitted!
