I’ve got these forks of uncertain vintage, with a remote that looks like this:

My old Revs had a blue knob on the lockout lever for adjusting compression, however there appears to be no such facility on these Rebas. Is it the case that I cannot adjust compression?

the blue compression adjust was a more expensive version of the 2007/8 vintage plastic lock out lever. I had one that I snapped the lever off (during a crash where it went nicely into my torso and then pulled out as it was still connected to the cable) and it was painfully slow to adjust the compression as it took many turns.

I later fitted the metal one like you have so they are compatible if you can find one. I preferred the metal one like you have as it looked less likely to stab me during a crash.

Ps no adjust. IIRc the lever is locked in when the fork is open and out when locked?

Only way I can think to add in some adjust is to change the pull ratio by fitting a different diameter knob on top of the fork.

I assume you had a poplock adjust lever previously? Can you not just replace the lever?

No, it was sold along with the Revs years ago.

All the blue knob did on the Revs was act like a cable barrel adjuster to increase a sort of progressive lockout. However it seems that partially pressing the current lever on the Rebas has no effect on compression until it hits the lockout point, so it looks like the damper itself isn’t really capable of lockout.

For a compression adjustment range you’ll need something like https://www.bike24.com/p2130801.html TFTuned should be able to help for around £80. Or you could try keeping your poplock gizmo and changing the compression damper oil to a heavier weight oil to prevent it blowing through its travel, or possibly a new air cap and add tokens. ???

Tokens do what? Reduce air chamber volume?

Tempted to go to a heavier oil. I do think it needs a little more.