I wouldn't continue with a treatment that is causing stinging and burning. This suggests you are sensitive to one or more of the ingredients.
There are other options - there's a weaker estriol cream which is 0.01% instead of 0.1%. however it is likely one of the carrier ingredients that is affecting you rather than the estriol itself.
There's also vagifem which can be used daily if needed on an ongoing basis, prasterone and ospemiphene oral tablets, although I am not sure the latter two are easily available on the NHS.
Also most VA in women on systemic HRT results from very subtherapeutic doses being used, which don't provide meaningful plasma levels of estrogen so it is worth reviewing this too.