You need a naturopathic doctor specialised in environmental toxicity. They have them here in the US; chelation of heavy metals is not a simple thing at all.
I have been getting Edta IV's for two months now and my levels of lead have slightly decreased - it is extremely slow. But many other heavy metals that were high or present have gone - beryllium, platinum, etc.
Heavy metal chelation does NOT happen after one IV!!! It takes months.
Also, I noticed by my results with only Edta chelation mercury and thallium were normal levels.
They only rose when I got DMPS IV - so obviously Edta has not much effect on thalium and mercury.
Maybe you could try DMPS. But you do need a naturopathic physician who knows his stuff...