Does anyone have a GF biscuit recipe that is for a harder biscuit (not rock hard but one that doesn't involve a lot of crumbs!!)? I made some chocolate ones yesterday but unfortunately they turned out too buttery and too crumbly...

It may pay to add more xanthan gum. I find the crumblier it is the more gum needed.

It also helps for biscuits to chill the mixture for an hour before cooking.

I have a tonne of recipes- some are working better than others....

Cheers for those tips Rachel.
There was actually no x gum in the recipe, and it wasn't even a GF recipe (silly me - I thought it was when I started preparing the ingredients, then realised it wasn't - it was dairy & egg free! ). But I thought it might work if I just swapped the plain flour with rice flour..!!
My first attempt at GF baking, but what else can I expect when it wasn't even a GF recipe to begin with!!

When converting a standard recipe to gf, it can help if you use a mixture of gf flours, rather than just one. I've actually given up on mixing my own and just use the Horleys gf flour. I've found this really good and with some recipes you can just swap the amounts of flour.
Keep trying - it takes persistance (and feels like you're learning to bake all over again!)
Good luck