I am talking worse case senario here ...that it is a real mess,with heavy deposits of moss.
260 sqm of tennis court you will need to clean heavy deposits by brush/hand due to access.
350sqm of carpark you could get a sweeper on £200/£250 a day.
I would remove as much of the heavy deposits by /brush/shovel /sweeper. I would then pressure wash it gently ...bearing in mind pressure washing tarmac can cause a right mess to clean up. It can also stripe very easily.
It would then need maintaining with moss and algae-side every 4/6 months depending on the location of it