"with free Kindles or tablets thrown in"...
I wouldn't class anything as free when it is part of a bundle that will probably cost 500 quid over the course of 2 years. Just spotted that Kogan (an Australian firm, but with a UK website for sales, in parallel with selling products on Ebay and Amazon for a while) has a couple of tablets just a little over the 115 pound mark.
As someone else had pointed out, not all tablets (esp the Chinese 'knock off' copies) won't work with the Google 'play store' (site for downloading Apps), so it seemed worth asking them, and getting them to confirm - as the pages I saw from my mobile didn't mention Google Play Store.
Have just checked and yes, their 10" Android v4 16 GB tablet (at 114 quid inc delivery) does use the play store (and has HDMI output, 3.5mm audio socket, 2 cameras, etc etc).
While the idea of a 'free' tablet in a phone deal is quite nice, I think the Xperia Tipo can be had for 7.50 a month from CPW and while spending 120 quid as a lump sum on a tablet may not seem ideal, it may mean you'd get a similar or better tablet and save 50 to 100 quid while doing so, just by keeping them separate, and it's not tied in with the mobile, so if there was some problem and you wanted to return the mobile within 7 days, you'd still have a tablet anyway, with an independent warranty.
Obviously it depends what the mobile contract throws in (minutes, texts, etc) but I'm still wary of ever thinking you're getting something for nothing, and invariably, the price they are paying is up to 30% less than the item retails at (though margin may be lower on tablets) so you are getting it on the 'never never' and perhaps paying 2 or 3 times what the 'free' tablet is really worth for the privilege of not laying out a lump sum.
Sorry to seem overly negative, but a simpler cashback deal seems a lot clearer in terms of the overall spend and what one gets for the money.