Want to get out of self assessment and current tax code

Hi


I am employed but for the last few years I have completed a self assessment to claim tax back for the business miles I do in my personal car as my employer pays me reduced mileage rate.


I am currently on tax code 1432L


I have just partially completed my self assessment for 2017/2018 and it advises I owe £79, this isn't a problem however really I would prefer my tax code to be changed to lower to account for overpayment. I can't find on the self assessment form if this is an option and have been cut off twice by HMRC.


From next month I change jobs and don't need to claim for tax from mileage - is there a way to get tax code put back down to standard rate 1185 as I don't want to go through the full year on higher allowance then be stung next year when it is put right. This is one reason why would like self assessment underpayment adjusted via tax code.


In reality I wish I hadn't ever started doing the tax claiming thing and just taken a hit and stayed on standard rate as it is not worth the hassle.


Any suggestions would be great as HMRC website not clear and phones just cut you off


Thanks