Hmm. Also mercury has a synergistic toxicity with aluminium among others.
I consider Chris Shade to be one of the top mercury toxicity expert. This interview is super interesting though it take sometime before it goes into the specific you might want to take a look at it. The first 5 minutes of the interview make it clear with Chris is truly a leading expert in the field and as the interview advance this only comes clearer.
His company patented a very specific mercury test and sell some detox product which might be worth looking at:
https://www.quicksilverscientific.com/testing/mercury-tri-test
Accessible in the UK, @teamsteem, do you know?
I don't know but possibly.