Beccys work is hilarious for sick, their policies mean that you're better to take a whole week off when you're sick as they count it on numbers of sick periods. So, if you have for example, Monday off, then feel OK, so go back on Tuesday, but take a turn for the worse on Wednesday, that would count as 2 periods of sick, where if you had the 3 days off, its only 1 period!! LOL.
One guy was on long term sick and went for a 3-week holiday in the USA and his bosses approved after he suggested it was for rehabilitation.