Looks like you've recieved alot of advice.
If you are not intending to settle permanently in the UK, as I would assume on a WHM. If you have earned ANY money in canada during the tax year, or have any intention of bringing anything you earned in the
UK home with you. I would suggest you declare your earnings in canada as well as the UK.
I went through a number of headaches getting this all sorted any the bottom line is that the advice I recieved from two separate Certified accountants was to file any income. Revenue canada will not tax you on anything you've already paid
taxes on, unless you have paid to little tax.
Having gone through an audit of my UK and canadian income last year I know this to be the case. The worst that will happen is that they demand proof of your employment within the uk.
As for taxes in the UK I would urge anyone whom is unfamiliar with the system to seek professional advice at least the first time you file, if you choose to do it yourself. It is invaluable.