Symptoms are  -

After starting the engine, EML always lights up after about a minute or so of running. (doesn't come on straight away. Other symptom is slightly high idle, that's NOT an air leak.

Paperclip test has shown 0130 Heated Exhaust Gas Oxygen (HEGO) sensor

(There are also codes for EGR and MAF - but these are my fault)

I believe the 0130 to be the only live code.

Any ideas? Is it the O2 sensor itself that fails, or is it another problem?

Advice please

With the sh1t3 that it was probably chucking down the exhaust I would say the Lambda sensor has probably been contaminated. Give it a good run once it's on the road before worrying too much though. It may clear when it gets good and hot.

Kevin