As a UK citizen can I visit my family in England during the validity of a 2 year work permit (IEC) for Canada? [closed]

tl;dr: you need to be admissible into Canada. Your IEC doesn't matter in this.

In general, the CIC website has answers to everything it's just impossible to find them. In this case, the answer is on the Prepare for arrival – International Experience Canada page:

Study and work permit holders from visa-exempt countries who received their permit on or before July 31, 2015 need an eTA to fly or transit to Canada.

Applicants who are issued an initial study or work permit on or after August 1, 2015 will automatically be issued an eTA along with their permit.

If you wish to exit and re-enter Canada by air, you will need to ensure that your eTA is still valid by consulting the Check Status Tool. If your eTA has expired, you will need to apply for a new one as soon as you can.

If you leave Canada while your work permit is still valid and return to continue working, the border services officer will re-assess your admissibility each time you enter Canada.

If you are still admissible, the border services officer will allow you to re-enter Canada with your original work permit.

The work permit states “This does not authorize re-entry.” This means the permit allows you to work in Canada after you have been legally admitted.

The work permit is not:

a visa or passport that will allow you entry to Canada, or a guarantee of your re-entry to Canada.

So if your eTA and IEC are both valid you should be good to go. Disclaimer: I am not a CIC agent and I do not even play one on television. Relying on this advice instead of calling the CIC is not necessarily the best idea -- however, common sense is on my side. To the contrary, bringing common sense to an immigration fight...