There's a £1 discount (promotion) if you buy 2 packs of '7dayshop "GOOD TO GO" AAA Pre Charged NiMh Rechargeable Batteries 850mAh 4 Pack' (other items are in this promotion too, e.g. 40 AA Alkaline batteries for £7.69
1 pack is £2.79 delivered (£69.8p per battery, which isn't bad)
2 packs are (2 x £2.79) - £1 = £4.58 delivered (57.3p per battery)
Their low self-discharge makes them good for long use scenarios, where you don't want to change the batteries too often. If you plan to use enough AAAs in your devices over Christmas, then 8 batteries might be a good quantity for you.
Which? magazine gave the AA version of these batteries a good review in May 2014.
"These 850mAh AAA Cell batteries are pre-charged & are 'GOOD TO GO' straight out of the pack.
LSD batteries (Low self discharge) retain 85% of their capacity after one year, compared to about half for normal NiMH batteries.
7dayshop rechargeable batteries are compatible and will re-charge with any good quality Ni-Mh battery charger.
AAA size batteries are also known as LR3, LR03 and MN2400."