Nope. Britain, and France for that matter, are different to Tunisia. Anywhere in Britain or France (or Spain, or the U.S. or Australia etc, etc) can be a target so the threat is generalised and it's both hard to predict where an attack might be. Given that tourists are spread out in lots of different areas and are generally independent travellers (rather than travellers staying in a compound belonging to a travel co), travel companies can't really be expected to provide high level security here, simply because of the nature of the tourist industry is so different.
In Tunisia large numbers of foreigners (who the travel cos knew would be a prized target) were concentrated in small areas, managed by those travel companies with barely any level of security.
And for the situation here to be comparable, you're looking at something like ISIS taking over Scotland and having easy access to England and being flooded with the necessary weaponry for attack. I suspect if that happened then, yes, tourists would expect more security here too.
Plus you have to remember that the UK government had a vested interest in not damaging the Tunisian tourist industry because it was the only example of what the West saw as a successful outcome to the Arab spring. They were essentially sending tourists as canaries down a mine, knowing they wouldn't warn people not to go unless there'd actually been significant numbers of deaths.
Anyway, we'll have to wait and see. But if the question is whether they should have foreseen the threat, I think these holiday makers have an extremely good case.