Blocked toilet.

I help a lady with down syndrome, and possibly autism, she has very limited understanding of language, and she will block the toilet with excessive amounts of toilet roll daily, sometimes several times.
Without giving you a long drawn out read, I’ll try to explain what I’ve already tried and why there are other things that I haven’t tried.
She makes it clear she doesn’t want assistance in the toilet, nor does she physically need it, so for her dignity and independence I would not challenge this. She it’s quite independent so will go to use the toilet without telling anyone, and begin the blocking, if she is asked when she it’s in the bathroom to stop putting toilet roll down the toilet, she will ignore the suggestion and continue!
It’s not possible to ration the toilet paper in public toilets or at the work opportunities project she goes to, as there are other people who need to use the toilets, and as it happens she it’s the only one who does this. At home it’s easy to keep on top off, by rationing (although doesn’t always go to plan) the main problem is the work opps, because in every other way she does not need much support, and it’s not practical for the staff there to monitor her all the time meaning it keeps happening.
The staff are at a loss as to what to do, as am I.
I’ve heard of this sort of toilet blocking being associated with autism, so I’m hoping someone has some helpful ideas! I’d like to say that when she does it, it seems to be more with the aim to finish the toilet roll rather than to actually block the toilet.
It’s costing the place a fortune in plumbers and I don’t want them to start charging her.
Thank you.

Maybe a reward system put in place would help.

Tell her she can have a piece of her favourite cake etc or 10p if she only uses
a small amount of toilet paper each time.

The simplest thing that I can think of is to use a different dispenser for the toilet roll - I’ve experienced a few in institutional places such as hospitals or schools where it’s a tedious process just to extract enough for normal usage - whether that would deter someone with your lady friends problems I don’t know, they may just see it as a challenge.

…another tack would be to collect up any rolls that are at least half used and keep those back for her usage - tell her it’s the last toilet roll in the building - when it’s gone it’s gone.

There are ‘single sheet’ dispensers which aren’t too costly. Would the lady just keep going? At least she couldn’t unroll dozens at a time. Perhaps it isn’t that she needs to empty the roll, just that she cannot control her pull and thinks once it’s unrolled, she has to dispose of it?
The only other thing I can think of is to have is to keep a nearly empty roll available but have a high shelf or locked cupboard which the rest of the staff know about with full rolls available in case of need. Secret stash? Of course that might result in the lady stuck in the loo because she has ‘run out’.
I can see that it is a problem and it won’t do to put the company off employing someone with difficulties. On the other hand, plumbers aren’t cheap.
Good luck.