Have you been to local Comet / Asda / Tesco / Currys?
Should be quite a selection, and so long as they have the Freeview symbol on them, should be ready to plug in, scan for stations, and use within 15 minutes.
Depending on where you live, Richer Sounds might also offer some bargain LCD TVs too, and if you spot a TV at price you like, check if www.Argos.co.uk selling it cheaper.
Only thing I would consider adding is that if you are going to set it up, then see if you can delete some of the channels.
For example, BBC and Sky news are perhaps enough without the Russian news station, CNN etc. Also zap CITV, CBeebies, and the 'adult' Babestation etc ones which could offend if grandparent happens to switch on late at night and skips through the channels.
Would also suggest deleting the 24 hour shopping channels, but it depends on whether grandparent might be tempted to buy costly items or consider the presenters friendly and 'company' (just that I know the mum of an acquaintance does put some channel on when morning TV caters mostly for under 10s or has depressing business news, and she wants something different).