Would like to buy a tablet PC for me Mum who’s in her 70’s. Budget up to £150. Any ideas?

I’m going to assume you actually mean a tablet, not a tablet with a integrated keyboard & detachable tablet (like a asus transformer)… so …Tesco’s Hudl, not seen one personally, but reviews are good/excellent for the money.
Gotta any clubcard points, you can use them to buy it.

Reviews here, here and here

Picked up 7″ tesco hudl (£119) for my mum (primarily to use skype, email and internet) Spec is darn good for the money. Also with the double up on club card points can get it for “free” or much cheapness if you have enough points. She hasn’t got/used it yet but i’m pretty impressed giving it its test run. (A 10″ might be slightly better for size/readability)

I know it is out of your budget and I will probably get shot down for it, but second hand iPad ? used a couple of other new tablets and found them very slow even compared to out iPad 3 which is 2 (?) years old.
Loads of apps as well, so you will be able to find anything you need, although I guess you will be after email, skype and safari ?

I got my Mum a Nexus 7 (first gen one a couple of years ago) – at the time that was £200 but now that the new one is out you can still pick up some of the older ones very cheap.

Currys and Carphone Warehouse are both doing the 1st Gen one for £139.99 and it’s still a good tablet.