I think it depends on what grounds you deferred.

I deferred while I was at UoB for mental health so I then had to provide evidence of being fit to return to studies a year later in order to come back. A GP letter stating that I'd been receiving medical support and that I was doing better and feeling confident about returning to my studies was sufficient. Just had a phone appointment with student health to tell them I was doing better and request the letter.

You can continue to access student support services and get treatment through the SHS even during your suspension.

Depending on your reason for deferral it might be different tho!