I don't think they could hire an EC set, they're used intensively, I think 12 sets out of 14 a day. If there were to be any hire-ins I'd expect it to be from EMT, as they're not used quite so intensively.
cant see it being a HST, even the trips they do thats supposed to be a HST has been 220's or 221's, today was the 8th journey that was supposed to be a HST in this calendar year but instead they layed on a 220,
which was the 1703 Birmingham to Edinburgh!!!!! FULL STANDING LOAD!!!!!