Sharing this in case it ever happens to anyone else.
On Friday evening I went to check posts and got red banner messages saying that my access had become restricted and to contact the community administrator.
This was nothing to do with posting on Lupus UK - where I usually post ( as it appeared no matter which Community I viewed.)
I was no longer able to post, reply, edit or delete across any Forum
Although I had the Posts tab, and could view posts, I had lost the Members tab.
I could still use chat and amend my Bio.
I checked the guidance given by HealthUnlocked about restrictions and to be honest I was really quite scared.
I used HealthUnlocked's Contact form to ask what had happened.
As it happened late on Friday, I needed to wait for today (Monday) rather than the advised 4 hours.
To my relief the restriction was due to there being 'suspected spam' in a post. HU checked and there was no spam, so my access got restored.
(I knew that if Lupus UK had found something they would have contacted me first with a warning.)
Just sharing this in case anyone else ever suddenly gets 'Restricted access' across all of HealthUnlocked without any prior warning. It could be due to something like this, so don't worry.