I have had holidays .. but other than that you are quite correct ... not had a day off sick since I started working in my current 'sphere' (profession) in 1986 ... I had been made redundant and was on 'gardening leave' at the time of my heart op in July 2017 ... back working in October 2017... and ever since...
Oyay Oyay Oyay .... hear the wise words of the recently knighted Sir Spurlock bin-Rasmalai ... and form an orderly queue on the South Bank.
I would argue that going off for a heart op is counted as sickness leave unless you weren’t paid for it
Nope ... my gardening leave started 2 weeks before the op ... would have been on gardening leave irrespective of what was going on in my life