Hi vxr8 and welcome to LEC. I hope you continue to find it a source of never ending help and a great resource of M100 information. Oh and lots of banter.
It would help if you put your location in your profile, so folks don't keep asking where you are whenever you need assistance.
With regard to the handbrake, does it click when you pull it on and does the lever stay put in any position you leave it when you do so? If so then the ratchet is working fine and the problem lies elsewhere.
If the ratchet is shot, then I am sure someone on here will have a handbrake assembly. If not try Douglas Valley Breakers or Lotusbits. DVB are expensive, but will have it. I do not know the source of the lever: may be Rover but more likely GM as so many parts were sourced by GM when they (read Lotus) developed the car.
Assuming the ratchet itself is OK ,then the 2 most likely issues are cable tension or rear calliper adjustment.
Cable adjustment is done under the centre console, so you need to remove it. There are 2 17mm nuts on each cable adjuster: tighten accordingly. It's a bit of a fiddle but do-able. You also need to check the position of the handbrake lever on the calliper whilst doing this: it should sit at rest (down) when cable is fully tightened.
Once you have done this and nothing has changed (!) then the rear callipers need to be adjusted. Possibly even stripped down cleaned and re-assembled with new rubbers etc. I think I need to do this too at some time shortly, so not having done it before I can only point you at the workshop manuals (see tab at top of page when logged in) and download. This is a bit fiddly, so you can also get them
here.
You can also have a search on this site for handbrake/calliper adjustment.
I would recommend getting the manuals anyway. Along with the parts catalogue they are extremely useful!
Handbrakes have never been a strong point on Elans (M100 and '60s models), so don't expect miracles, but people have managed to get them to work sufficiently for the MOT and reasonable normal use.
Good luck
La vie passe vite: vivez la avec élan.
Elan SE turbo 1992
Emira 2023
Mercedes Benz C200 estate
Lotus Evija Danish edition