does anybody know where I can get "AO" size drawings photocopied or preferably reduced, or scanned onto a USB stick?

I'm pretty sure Birkenhead Central Library has A0 copying facilities, but you'd better phone and ask.

Prontaprint are the obvious commercial business, staples might be able to as well.

You can do it with a decent camera - get a good distance away, at least 10 times the document size away and using optical zoom (I've done it down a stairwell before now).

C S Copiers in Seaview Road Liscard

Staples by wickes

I'll start with the Library tomorrow, thanks.