Lynz, hit on some of the negatives & positives of what a new settler might observe or find living in the
UKThe observant Canadian will find as much negativeness as the Brits portray.
Being an older expat Brit (& trying not to sound off like one) who has lived as a settler in five different countries in his lifetime - is that when you make a move to some other place in your 20-40's from your place of birth & having grown up in it, you have to deal with many issues (besides home sickness) from first adjustments, settling in, cultural to finding a job.
The OP says they have a job possibility lined up (considering it) - that in itself overcomes a big obstacle.
If a job opportunity is lined up & you have not at least been over to look & see before making the big move or accepting the position - well you can only expect the worse.
DRPHIL, my suggestion to you is that you take a trip over & go see - it'll cost you a couple of grand max. Explore your options, look at the surroundings, check out accommodations, go to the pub, walk around the supermarkets, travel on the local bus & train, read many of the local newspapers, sit idle & observe the locals - only you will know... the answer for you can't simply be found on this forum - everyones experience is different, which may be a long mile from where your head is at.
On Brits compared to Canadians - I'd agree with Lynz, they (its by their nature) probably whinge about almost anything - equal, more or less to Americans & for those who have had any dealings with Brits - you'd know that they moan at least 25 % more than Canadians.
You can find fault in almost anything anywhere with any single thing, you can compare your new surroundings to back-home & all of the things that are way better in Canada - such as cleaness, big open spaces, the winter or summers.
I always say 'get on with it', after all it was you (or could be you) that decides (ed) to make the leap of faith & if you cant cope or it doesn't work out [next option] - then move on [dont let the grass grow under your feet] or move back home ... its all too easy to moan, find fault & eventually give up out of frustration or that you run out of money
In the UK or anyhere else, what would be wrong with having 3-4 part time jobs including contract work totaling 45-60 hours per week, even at minimum wage

Disclaimer: I am not an immigration expert & anything that I post on visa & immigration is based soley on more than 30 years of personal experience & interaction with the UKBA & Home office.