Chain/sprockets recommendation pls

After over an hour scrubbing with a stuff brush and half a litre of diesel, this was the best I could get:

Although at a glance it look ok, and despite the fact that some of the links are nice and flexible, there are too many that simply aren't and the rust inside the roller looks pretty terminal.

So, it's time for a new chain.

The bike came with a 45T rear sprocket already fitted, with teeth that look like Gonzo's nose

I've removed the sprocket and carrier from the rear wheel and tried removing the 5 retaining studs/nuts. As soon as I pulled the carrier/sprocket out I could feel that 2 of the studs felt a little loose. The other 3 locking nuts came off their threaded studs, no problem, but the 2 loose ones appear to have been over-tightened by the previous owner (only takes a few minutes to hunt down and check the torque settings FFS) resulting in stripped thread - so the nuts just span. After a bit of TLC with a butane torch, Dremmel and a cold chisel we got this:

So I've ordered 2 new studs (£10 each!) from the Rocket Centre (nearest Aprilia Dealer I think). Decided I was better getting 2 new as they'll be here Monday rather than buying some used ones off ebay and waiting 1-2 weeks for them.

So anyways, I'm removing the 110-link chain and 47T rear sprocket that was fitted. Gonna buy a new chain and sprocket and am looking for recommendations. I'll only be using the bike on the road and don't go balls-out everywhere. Previously fitted a gold DID X-ring chain to my Ninja and JT sprockets so happy to go down that route again unless people advise otherwise. Just need a recommendation now as to sprocket sizes and number of links in the chain to suit...?