Thanks ladies. Still no answer but I'll update you when an email comes through. No doubt it'll be some standard email but hopefully there are more contact details to find out more info if that is the case.
As for the blacklisting, I looked it up earlier and found on The Telegraph website a piece confirming that agencies don't blacklist properties anymore. But maybe specific places are flagged for warning? I don't know, it seems such a nuisance.
Oh and Lellow, I'm in a similar situation still getting previous tenants post. Several weeks back we had a few items delivered for them. I had a couple of 'whilst you were out' cards from royal mail which I obviously couldn't pick up but also had 2 items delivered when I was in. Didn't know what to do with them as there was no return address and then one day recently, previous tenant slips a note in my door saying she had accidently ordered items to my address and could I ring her to arrange for them to be picked up?! I told her to update her address immediately as I was receiving a tonne of mail for her and then she sent her husband round to pick them up! Who 'accidently' gets items delivered to the completely wrong address? It just seemed so odd.