Just a note to those needing to contact HMRC, I had need to contact regarding a client's 2/20 VAT Return (MTD info not feeding into software). I was going to phone, but elected to try the webchat instead.
They opened with an apology if I'd had to wait, almost instantly (i.e. I hadn't had to wait at all).
Issue resolved in a couple of minutes. The advisor was working remotely. Perhaps this should be a permanent state of affairs if it leads to such an improvement in CS from HMRC.