Update:
LA rang this morning, to say that he'd had an email from the DPS and it appeared they had agreed to repay £255 to us, £270 to the tenants.
He said he had to read it a couple of times to quite believe it, but if we were happy to let go of the other £15 we'd disputed, all he had to do was click to say he approved of the repayment.
Following a couple of hours of euphoric disbelief that it could all be resolved so easily, I'm now back to wondering (and worrying) that perhaps he's misunderstood, and that the repayment agreement is actually only for the tenants to receive the undisputed amount.
If that was the case, wouldn't the DPS return ONLY the undisputed amount - which was £255 to the tenants, NOT £270?
I'm utterly confused - we also recieved a text from the lead tenant this morning, asking us what the £270 was for.... :S