They DO exist!
DS2 had his developmental check (6mths) today, and HV asked about weaning. i started trying to explain BLW, thinking she'd think i was a martian, but she knew what i meant, and thought it was great. Didn't tell me off for him sleeping with us, and when i said he tended to vomit up food so i wasn't bothering to give much at all, she just said he probably wasn't ready yet and not to worry because there's plenty of time.
And she said i'd made her day as i was still breastfeeding, because she rarely meets anyone who is at this stage, so i'm a star apparently.
So, good HVs do exist ladies!