Sadly, my own favourites are no longer trading.
But, have you considered using 3x or so NHS "holiday makers" (and "busman holidays", at that)? At least that way you would know what (who) you are getting (easy to check out beforehand). Probably cheaper that way, too.
Otherwise, you might also come across a retired tech who wouldn't mind doing a few months "just for old times' sake" (and no, I'm not volunteering myself).
Either way, may I suggest that you should be thinking in terms of the "bloke" ... rather than the "company". In short, you want someone who will stay the course over three months of "PM" (without much supervision, I'm guessing).