Just wanted to come back in here and say thanks to all of you.
Firstly, I went and drilled a 1/4" hole, useda #6-10 anchor/fastener but used a #10 screw from the next set up instead of the #8 the #6-10s came with. Here's how it looks, complete with the same stripped hole reused just made a bit bigger, self evident in the photos.
I loved the imperial/metric comments. But I wanted to appreciate you all for helping non confrontationally a person who had a pretty basic request for help. But, as I think I said, I'm admittedly a bit of a noob. As I said in another thread, there used to be although it's not so bad now, a bit of an attitude 10 years ago about going into diy forums and asking what were perceived to be basic questions.
And it still permeates the field online a little. In fact I landed here because places I usually tend to go to for help that are North American sites (I'm in Canada) invariably lead me to people ridiculing my questions or being sarcastic which is useless for learning anything so I thought, being an anglophile, blighty-loving, Yorkshire Gold drinking, Midsomer Murder watching person, that Brits might be able to help me in a more friendly way and so far I've not been disappointed.
Ta.