Cheap Acer Laptop Battery: Help Wanted

I’m looking for anyone with tips about cheap laptop battery retailers.

My laptop (an Acer Aspire 5003 wlmi) battery packed in ages ago and it’s a pain in the arse having a laptop that has to be plugged in.  The laptop was only £400 so it would seem a bit of a waste to spend too much on a new battery.

I could get one for about £35-£40 from a few different places but most of them look a little bit shakey (and many are the same site with different names).

So does anyone have any experiences with any of the following:

or anywhere else where I can pick up a cheap battery for the aforementioned Acer Aspire 5003 wlmi laptop?

Update: I’ve ordered from after finding a voucher code for 10% off everything, so it was £38.98 delivered (hopefully). Will report back if/when it arrives.