In some post offices I have seen posters advertising Pixinpost.co.uk from Snapfish so seems like a new partnership between the two companies. They are also giving out free vouchers worth £5 of credit with no minimum spend.
I'm from the west Midlands so not sure if nationwide. But you can just visithttp://www.pixinpost.co.uk
and log in or register and then use one of the codes on the leaflets (eg LB87XG2WQ33B) for a free £5 credit.
The credit gets you up to £5 off whatever you want to buy, but doesn't apply to delivery costs (and these vary by item). So if an item is less than £5 you get it 'free', but you won't get any change from the code, and you have to pay the full delivery.
Examples of what you can get in time for Christmas:
99p for 7"x5" Christmas photo card - norm £3.98 (1.99 + 99p del)
£1.99 for 15"x10" photo poster - norm £5.98 (£3.99 + £1.99 del)
£2.49 for Photo keyring or magnet - norm £5.48 (£2.98 + £2.49 del)
£2.99 for 50 6"x4"photo prints - norm £7.99 (£5 + £2.99 del)
£3.98 for 6"x4" 20 -page photo book - norm £8.98 (£6.99 + £1.99 del)
£5.98 for Photo mug - norm £10.98 (£7.99 + £2.99 del)
Last order date for Christmas is 20/12/16