A1C of 70 I have not heard of, unless it is the new system use in UK, which would be in mmol/mol (IFCC)
Unless you meant 7.0 % ?
I found the UK new value system, scroll down to see the many charts in there.

https://www.dietvsdisease.org/normal-hba1c-rang...

Found another site to calculate conversion https://www.hba1cnet.com/hba1c-calculator/

By entering your 70 the results are below

HbA1c in mmol/mol (IFCC) 70
in % (DCCT/NGSP) 8.6
Average blood glucose in mg/dL 199.11
in mmol/L 11.05

Hope this helps.