I have a coworker who, when he got out of school in the 90s, got hired to write COBOL. There's a ton of COBOL out there, and why not? As much as "waterfall" is a fiction, high-spec, super-detailed-spec projects actually do have some advantages as they are usually well thought out. That is where COBOL played, and why those apps have run since the 70s.
Sometimes the entire specification really does exist before you start. Certain kinds of software applications have not had substantive new functionality in decades, so everyone knows what a complete implementation of it looks like.
It probably was hard to hire in the mid 2000s. I applied for a job as fraud/engineer/technical investigator and didn't get it. The rejection phone call was we noticed you have "Pascal" on your resume, can you please come and help us out to document and extend a Delphi application for the same pay, we have created a job for you? I did.
£60k seems a little low for a "senior" position in central London. Although you do get final salary pension, slightly above average holidays (30 plus bank holidays), and free TFL travel.