They look too worn to be catwalk/photshoot returns, so i’d go with dead relatives or flea market jobs.
I will add, whilst £3.5K for a pair of shoes is ridiculous, it is not hard to spend £200-£400 on a good pair of shoes/boots that are not completely bespoke fitted (though some offer a service of paying £80-£150 to get your own last made, but this means shopping form the same maker for the rest of your life).
I’ve got 2 pairs o Church’s shoes each around the £400 mark, but i’ve had them 10 years and they look like new but fit like old worn in slippers. i’ve also got a £300 pair of RM Williams boots that i abuse alot**, and are still looking good with a scrub up. In the same time the missus has bought in excess of 100 pairs of wellies, boots, shoes, high-heels etc which will of cost far, far more…
**i learnt my lesson with Timberland boots being utter tosh..
my view is to treat Shoes as an investment, look after your footwear, and they’ll look after you.