After more research I worked out that Caprimec and noromectin are both mectins so I decided to use Panacur instead. Last time 2x the dose gave 50% reduction so now we did 3x dose. Pilly got 12 ml or Pan100. Monty 15. Both took it easily. Tag's dose was 15. I loaded to 18 then 10. She took most of it.
The idea this time is to treat 3 times, 10 days apart, with tests at every point.
Then move to clean paddock 10 days after last dose.
Before the first treatment, I collected a sample to give me a base line. Note NO treatment had been given since receiving high results while we were away.
At the end of June, Monty was 720 and Tag 1860. I had not tested Pilly as she was 0 in early June.
The results for this pre-treatment samples came late.
Meanwhile on 28August I repeated the doses for Pilly and Monty and in 29th for Tag (she took it well this time.
Then I got the first results back and realised I should have only treated Tag.
This is what was found, which was very interesting given no treatment had been given since previous high results. How did Monty fix himself?
So after the first treatment, Monty doubled (I think we just assume he was about the same) and Tag was nearly 1/2. We'll continue monitoring them all but treating just Tag.
And after one more treatment for Tag, we are finally down to an acceptable level. We'll see for how long… no paddock move.