Here's what happened - I phoned up on Monday night to make a 6:30 booking for Tuesday at HoD 1. The woman I spoke to said fine, but please call again on Tuesday by 11 am to confirm.
Not a problem, so I called again on Tuesday morning to confirm. I spoke to the same woman, who said fine, I'll text you the address. You should note that I was phoning a land line. I was at work and busy, so didn't check my punting phone again until 4pm - there was no message. I called back, but got cut off by the maid. I called again at 5:30 - this time it went straight to voicemail.
With no idea what was happening, and no wish to slog into central London during rush hour on the off chance, I thought it was time to make other arrangements. At 6:40 I got a shirty phone call from the maid (on a different number - a mobile) asking why I hadn't turned up - that would be because I had no idea where I was supposed to be turning up to.
This was the WG I intended to see:https://www.adultwork.com/2143707
In future I'll be booking her independently and suggest you do the same. The booking at HoD used to be smooth, but the previous time I tried to book I got messed around too. Telling the punter where the flat is is basic stuff - I have no idea how you can fail to do that.
Unfortunately this wasn't my only bad experience yesterday...