Off the top of my head. Unless it’s changed, the only options when joining are 70%/100% contracts. We then get offered optional winter leave each year, where you can take upto 5 months off at 50% pay and various other options if you want to.
But it is always full time in summer.
I believe 70% you do full time in peak period, then from October you work a max of 10 days I think, then november/december off then max 10 days in Jan/Feb/Mar.
That might not be completely accurate but it roughly works like that.