Problems with line film in Rollei HC dev

I had my first go today at attempting to make a halftone image using ortho litho / line film and Rollei HC dev.

I decided to practice with some old Ilford Technical Line film that I found at the back of the darkroom gathering dust, nicely packaged, with a few sheets used. I had tested the film a few days ago making a transparency and developing it in some normal working strength print developer, and got a great image with constant tone.

Then my bottle of Rollei HC High Contrast developer turned up today, so I scuttled off down to the darkroom to try it out.

First test strip came out black, completely. I ended up doing test strips as dim as 1 second f/45 but still - black.

I then chucked an unexposed strip in the HC dev and it also went very dark, not *quite* black but almost.

I wonder, is the film damaged through age or light exposure at some point, does the emulsion not "agree" with the HC dev chemistry, or possibly am I doing something wrong. Also, I know the safelight recommendation is dark brown and I'm using red, but to be frank I've used paper that called for a brown safelight and it's been fine.

Hmmmmmmmmmmses....*scratches head* Any thoughts welcome.