Thanks (again!) all.
I've got a 28mm spade bit for the button holes, which I was happy with. It did "pop" out the bottom of the wood on my trial chipboard, but I'll get round that with a second scrap of wood clamped underneath next time.
I'd seen what features a Forstner bit had, but none seemed to relate to the cabinet except for holes which I was already happy I'd sorted :-) Still, if I get a router I may as well get a Forstner bit if they do holes easier/better.