English more or less covered it, I'm a Londoner, and for me it goes
Penny, (1p) pronounced pee,
5p, 10p, 20p, 50p, I would also call it change or shrapnel, as in "I am skint today, all I have is a pocket full of shrapnel."
Then there's a quid/knicker or 2 quid/knicker, £1 or £2. £5, a fiver, £10, a tenner. Then there's there's the cockney,
Score, £20, pony, £25, ton, £100, and a grand, which is a thousand pounds.