I can speak for contemporary British usage. The others not so much.
£1.01 is a fairly uncommon amount to hear in a shop, because prices near the pound are usually £n.99 or £n.95 etc., in which case "n ninety-nine" etc. is de rigueur.
Recently though, a law was introduced whereby plastic bags have to be charged to the customer at 5p each. When this is added to a purchase of 99p, £1.04 would no longer be uncommon and colloquially usage would usually be "one oh four".
Context would make the units apparent. The purchaser would "know" this was a small amount and therefore around the one pound mark, so "one oh four" would be automatically understood as being £1.04.
Exactly the same applies to £1.01, which would be voiced "one oh one", or perhaps "one pound oh one".
You might hear "one pound and one p" (if the vendor wanted to be particularly precise), as "p" is standard for announcing the units of pence.
We hardly ever say "pennies" or "pence". It's practically always "p" pronounced "pee". Despite the opportunity here for ribald jokes, this is practically unnoticed by contemporary Brits.
£101 would be spoken "a hundred and one (pounds)".