well it would help but it may only be a little. Can you add grass clippings to the dry bits?

The dry bits are grass clippings!

Can you add veggie food waste then? That does tend to rot down to mush and keeps grass moist.

I have a plastic compost bin which I empty from the flap at the bottom from time to time. Somhairle is spot on. You need to layer your material with grass clippings, cut up plant waste and vegetable waste. If you have a compost heap which you empty on an annual basis, you need to turn the material from top to bottom regularly and perhaps have two bins going at the same time.

We have 3 bins, In, Pending and Out. Each one is 6 feet by 6 feet. All biodegradable material from all sources is added to the heap. The only reason we have so much grass cuttings is that our neighbour is a greens keeper and he brought the scarifyings for us. 7 huge bags of it.
If I had been really worried about the dry bits I would have added water as I turned it.
I think the weird weather and the Holly tree behind the heap has contributed to the dryness.
I did pour 800 (yes that much) litres of water on it and none ran out of the sides.
Really I was asking about drainage rather than composting. The compost in the Out bin is real Monty Don quality.