ASD referral-out of the blue

[JimmyJam2019]

I've spoken to the HV about a few of my 4yo daughter's behaviours over the last couple of years and been fobbed off that they are a phase. Excessive masturbation and disrupted sleep (leading to an overtired child who loses her sparkle as a result) being two stand out ones.
She's been in reception class half a term and we've already been called in for a meeting with her teacher and SENCO about an ASD referral.
They are concerned she hasn't made any concrete friendships yet, gets upset by loud, sudden noises and her speech isn't very engaging.
She's a baby of her year and she's spent very little time with other children her age since March so surely some extra time to settle in is to be expected rather than jumping to ASD conclusions?
I think the masturbation and sleep issues are anxiety based but no-one wants to deal with these as she is physically well.
A referral has been made for ASD assessment and we are getting a hospital appointment with a paediatrician about the hearing.
She's always been a happy, sociable girl, who has always communicated well with what I would say are the usual challenging behaviours for her age with a couple of concerns but I am a natural worrier.
Does any of this make sense? What should we be doing in the meantime?

It makes sense, as you start your post complaining that you have talked to your HV more than once, over a couple of years, about her behaviours, and have been 'fobbed off'.
However, now you are saying someone else has also recognised some of her behaviours might not be neurotypical, you think they shouldn't suggest getting some further investigation ?

Re 'what you should be doing in the meantime' - I would ask if you can have another appointment with the teacher and the SENCo. Whether or not your dd gets a diagnosis of autism, of something else, or doesn't get a diagnosis in some ways is only part of the bigger picture. If you have had a meeting with the SENCo and a referral, only 1/2 a term into a very busy school year, then it suggests that she has significant difficulties in accessing the whole, wider curriculum (so, including social, not just academic). I would ask what the are putting in to place to support her at school, and what you can do to support her at home. I'd want to find out really specifically what it is she is doing / not doing , saying / not saying, understanding / no understanding, and I'd want to find out any suggestions for helping her to do the things she isn't managing at the moment.

@backforgood thanks for your comments. My concerns with sleep etc are still being fobbed off as a phase. The matters school are mentioning have never been mentioned by her childcare or nursery teacher (at the same school!) before in parents evenings. She has been sociable and played well with children before this school year, which is why I am baffled.

Have you spoken to your GP about the anxiety? Could it be that she is experiencing some social anxiety at school? Would you feel a CAMHS referral more appropriate?