we have used nannies/mothers helps beofre.
both as ABA tutors (ie employed for x hours a week) and also recently had a live-in nanny, who we trained up in "ABA ways" - dd1 now at ABA school, and dd2 started at pre-school, so was not so much the use as an ABA tutor, but obviously, anyone who works with dd1 needs ot be well versed in how we handle her etc.
so, going back a bit, we have had:
a mother's help/general purpose student, who was dd1's ABA tutor. she was paid £10/hour.
an ABA tutor, who did the odd bit of general purpose mother's help stuff. she got £8/hour.
and the nanny we had was on about £18k/year - live in, 50 hour week plus 2 evenings babysitting. all childcare duties - food, washing, tidying etc, as well as school runs, and general playing with/childcare. standard nanny stuff.
we didn't pay the nanny more because dd1 is ASD - you can end up paying a whole lot more, especially if you go via SNAP agency etc - but mostly what we are asking is normal nannying (albeit "normal" for younger children, maybe) plus a little extra personal help, so it is attitude that is important to us (ie not someone who will look at dd and think "hmm, you're 6, you shoud be doign X,Y,Z") not experience of ASD as such (since we will train up to be well versed in our habits, and in dd1, etc)