Having had Jax's paws shorn yesterday we've now had our first day without a new incident in a week! Hoorraayy! I checked his paws last thing last night and no new seeds. I checked again this morning and again nothing. He's stopped limping too which is clearly a sign his current wounds are on the mend. But only short-lived relief I expect!
The vet told me that it really is down to the individual dog rather than the breed whether they suffer with seeds or not. She gave an example of two cockers from the same litter, one has never had an embedded seed and the other was like Jax, always getting them and ending up with her.
I spoke to our breeder yesterday too and she has never had any problems with her SWDs. So I'm inclined to agree with the vet. Individual dog and individual circumstances. Just sods law its us!