I understand from reading your blog that you do not recommend oral care products containing sodium bicarbonate (baking soda). However, Retardex in the UK does contain sodium bicarbonate according to the list of ingredients on its packaging (aqua, trisodium phosphate, citric acid, sodium bicarbonate, sodium chlorite). Whilst Closys does not appear to contain sodium bicarbonate according to cosmeticsdatabase.com, I would question this discrepancy between the two products as it is reasonable to assume that Retardex and Closys are identical.
I think the products are as close as you will find today. Obviously there may be differences - and I am sorry that getting exact products in various countries is so difficult.
One of the reasons I stick to the products I recommend with such tenacity, is that I know they will work - for anyone! These are not products "created" by me - these are products that (as an observant dentist) I noticed worked for patients.
My upcoming book "Kiss Your Dentist Goodbye" describes my 35 year journey as a dentist - and how I discovered these products, and why this system works to positively affect teeth.