Hmm.. personally I thought it looked something more like this
I think that is wonderful.
I've wanted a Moth trap for a while; I seem to alternate between wanting to make my own and then thinking I'll save up and buy one. I may just buy a MV bulb and set up a white sheet.
What to do...
Well my Mum and Dad got it from Anglian Supplies there really good for beginner moth traps and do ones that are less bright (to stop disturbing your neighbours). I reccomend not making your own because you'll have to go through loads of technical difficulties so i reccomend getting the skinners moth trap (thats what I've got) sadly I think they cost 116 pounds but ifn your intrested i'd get one, Oh and it doesn't matter if your in an urban place obviously you won't get the same amount but I get enough in a wiltshire town!!!!
I am not sure what time of year this was taken, but I would wager this is a worn Square-spot Rustic (xestia xanthographa). They can be quite variable and tend to keep that 'Square' shaped stigma.
No Biff they just come in a variety of colors and sizes, as you get more into this you'll learn which ones are like this. There are a certain amount of moths that will also look different in the northern regions of the UK, versus the South. Those books I mentioned in the other post will help you with that too 'Field Guide to the Moths of Great Britain and Irelend' they are a must have for any serious moth'er