Heading to UK for 6 weeks, would like a PP SIM for the iPad – data only as will have phones anyway. What’s best and where do you get them.

Ta

I’ve just bought a Three data only SIM card, 3GB valid for 3 months from first use (no registration etc. just pop it in and go). Sub £12 from Ebay if you can get it ordered to a UK address.

Otherwise Giffgaff – £7.50 for 1GB valid for 30 days (or £5/500mb).

Giffgaff uses O2’s network which isn’t as good for data/3G coverage IME (YMMV). You’ll also have to register it and top it up.

Edit:
£12.06 from Amazon

£11.90 from eBay

The 3 network deals from Amazon or eBay linked to in the previous post are the way to go. Just check that 3 has coverage in the areas that you intend to visit 3 UK Cover
If you are likely to use more than 3GB it is cheaper to buy 2 SIMs as it costs £15 to top up with 3GB.
I used this when visiting the UK earlier this year and it worked really well.