There's more than Panasonic that are fully HD, not "HD ready". Those sold by John Lewis includes Sony, Samsung, Philips, Toshiba, LG as well as Panasonic.
As regards John Lewis & the 5 year guarantee - I asked what this really meant when we purchased our TV there & we were told that if the TV became unrepairable then we'd have an allowance towards a new TV, based partly on the age of the one that had died - ie not necessarily a full replacement. I asked because a relative's 2+ year old Panasonic had died within the previous month - it was bought from a local family shop who lent a set for few days and then delivered (and set up) the nearest new equivalent which turned out to be full HD (old one wasn't even HD ready). The shop wasn't the cheapest, but I doubt their service could have been bettered. So, if I'd been in the same area as relative I'd have chosen the local shop, not John Lewis!