South African Drivers License - British Embassy letter required???

Hi All South Africans living in France...
I have a South African drivers license and lived 12 years in Cape Town, and while I know that it can be swapped for a French one within the first year of living in France... my local prefecture is asking me for a letter from the British Embassy in SA to state that I lived in South Africa for more than 6 months during the year that I got my license (2005), and that I have now left the country.
I have tried giving the prefecture all sorts of other documentation to show that I lived in South Africa at that time, but they are insistent on this particular letter... which the British Embassy will not write. (I have a British Passport)
Does anyone have any advice of who I can turn to - or where I might be able to get a letter of this sort?
Thanks in advance!
Alice

try www.gov.uk/browse/driving/driving-licences or try finding the contact email for the conservative MP Patrick McLoughlin

Appreciate your advice/thoughts on this. The "difficulty" is that my Drivers License is a South African Drivers License - as I was living there at the time (and for a period of nearly 12 years)... but because I am now in France as an EU Cititzen (with a British Passport), the French Prefecture want the letter to come from the British Embassy in South Africa!

Hi Alice,

I will be having the same case as yours. Philippine nationality with UAE Driving license when I move to France this summer.

Did you manage to exchange your SA license to french? Can you advise what is the process of exchanging DL?

Thanks in advance!
Will