One of those jobs on my Round Toit list. What did you use to seal the blocks?
I used the Wickes sealer. I did the edging bricks by hand with a brush then used a Wickes telescopic-pole-roller and bucket for the majority. You don't need to, but I've given it two coats to get a deeper sheen and more protection. Once the joints are done I think it'll look great. And, more importantly stay that way longer. Yesterday evening I could see the rain beading on it.
Part of it is quite shaded so was going a bit green. I've washed my cars on it a lot so all the black water from the wheels would have been settling on it, etc etc.
Now it should be easy to keep in looking good with a quick blast with the pressure washer.
Be careful what you buy - some of them are water based and/or a bit rubbish. This one came with good reviews and really worked for me.