When applying for software engineering/development jobs should I keep my CV/resume on 1 or 2 pages?
In the UK you write a CV, which contains details on where you've worked and studied, a personal profile, list of skills, and information on hobbies. It should run to two pages of smartly-formatted prose combined with bullet-lists.
A résumé is a much more simple bullet-list of where you've worked, runs to about half a page to a page. It's limited to what skills you learned in what job.
Note: if you're looking for a dev job in the UK, make your CV really bloody good; there's barely any jobs and competition is very fierce.
The next version will probably finally be expanded to 2 pages.
If you haven't already you should set up a GitHub/GitLab/BitBucket account and upload some personal project work. Include a link on your CV so people can check out your code.
A simple Google search for "developer cv" yields tons of useful info - just be sure to apply it properly, don't just blindly follow everything the internet tells you