As others have said, in lieu of a recent degree, you need a portfolio. Happy to help you understand how your previous experiences or projects might map to a portfolio - work with what you've got :) This doesn't necessarily have to be totally technical; "soft skills" are core too. Also, LinkedIn is the way to go for finding local work. Happy to critique your current profile too.
In the past I have helped several people, including international candidates, navigate the UK recruitment process to secure positions in this field and academia.
Question:
- When did you get your previous degree?
Depending on when this was, this could enable you to apply for graduate programmes.
Likewise, as someone mentioned below, leveraging your undergraduate knowledge to position yourself for a job at the intersection of software development and that domain might be a good option.