Thanks for the assistance
@frugledoc A colleague of mine requests her higher rate tax refund (from SIPP contributions) by sending HMRC a letter rather than filling out a self assessment but I haven't tried this myself yet.
If I understood you correctly - to work out the taxable income I subtract the total contribution then add back the higher rate tax refund but not the basic refund directly added to the SIPP?
Then if I contribute an amount equal to or greater than:
[ Gross pay - (DB pension contributions plus childcare vouchers) - 50k ] * 1.33
r...then I avoid the need to pay higher rate income charge altogether and possibly avoid the need to do self-assessment if the letter method works for claiming the tax refund... (I wanted to lay it all out here as it may help someone else here... and laying it out helps me understand it too)
I've contributed amounts in this region previously but this has been an expensive year as we have moved down the country (UK) to be closer to family and while we've reduced both commutes massively, gained more time back with kids, reduced childcare time and cost etc. - which is totally worth it - we've used up some emergency fund and had a brief break in income between Mr Acorn's jobs.
It'll be tight but with the advantages I'm going to add this figure to the 'goals' list for this year - although I won't know what the final figure is til near the end of the tax year...