Childcare vouchers - higher rate taxpayer

[LaPufalina]

Does anyone know what happens if you change to being a higher-rate taxpayer in the current tax year after receiving vouchers at the basic rate amount? I was on mat leave for half of this tax year (paid just SMP for three months and nothing for three months), so although I'm usually a higher-rate taxpayer, I'm basic rate for this year. I'm due a bonus in March which might well (just) take me back into the higher bracket for the year.
Does anyone know if that then changes my entitlement for the whole tax year? As I'll have had 11 months at £243/basic rate entitlement as opposed to £121(?), would I then owe back half of them? How would that even work?
To further complicate matters, I'm going to switch to tax free childcare so I wonder if I might be better cancelling my vouchers from Feb so I don't have a higher-rate taxpayer month in March!

Just found an answer but might help anyone else looking! Should've checked first sorry!
www.childcarevouchers.co.uk/parents/parent-support/parent-faqs/
Discretionary and performance related bonuses are not included in this assessment. Once completed, this assessment will remain valid until the start of the next tax year, regardless of any changes in circumstances throughout the year; therefore your tax and NI exemption will not change throughout the year.

OP I had a similar thread on this too- I receive basic rate vouchers but my bonus in January pushes me into the higher bracket.
My payroll company dont even seem sure of the rule and said its fine as long as my bonus isnt guaranteed with my salary so im continuing requesting the full £243. Not sure this is entirely correct, so Im expecting to have a bill when I self cert next year to return my child benefit also. Its a confusing mess