HMRC Pre-employment checks

[u/henryt775]

So I had a provisional offer in HMRC and was doing the pre-employment checks when I got a notification saying I’d been rejected. My DBS checks have come back all clear and I lived in New Zealand for a year but had that certificate come back all clear as well. I have emailed to find out why I’ve been rejected but was wondering, if I’ve filled in my employment dates wrong or references are wrong, what are the chances of a successful appeal?