I've got a decent mask, a proper one with a choice of replaceable filters, that fits properly.
I haven't started building it yet, on account of not having moved in yet. Move in date is Monday, but the vendors emailed the estate agent to say they'd moved out a couple of days ago, so we went up there today, to deposit a few plants in big pots round the back, and to measure the barn for the workshop. However, as we approached, there were two removal vans in the drive, and some dickhead had parked a 4x4 on the otherwise nice grass verge. Bastards, keeping up the lying, right to the bitter end. I'll ask the estate agent on Monday, when I collect the keys, if they have dropped some in to them since Saturday afternoon (they close at 1300 Saturday). If not, then I'll be instructing my solicitor to reclaim the cost of changing ALL the locks from them.
I was going to change them for better quality ones anyway, but not returning all the keys is downright bloody fraudulent. We shall see.