bookworm, apologies for referring to the area as a TRA. I drove to Elvington so hadn't needed to read the NOTAMs.
We had been discussing TRA whilst I was there and I assumed, wrongly as it turns out, that one was in existence for the competition. It doesn't, however, excuse the behaviour of the transgressors - only an idiot would go near the place if he or she had read the NOTAM.