[user104658]

Originally Posted by Cherie

I might change the title to Cherie's grab that free cash thread

https://www.gov.uk/married-couples-allowance

Overview
Married Couple’s Allowance could reduce your tax bill by between £345 and £891.50 a year.
You can claim Married Couple’s Allowance if all the following apply:
you’re married or in a civil partnership
you’re living with your spouse or civil partner
one of you was born before 6 April 1935 LT

I don't think this is really relevant as it only applies to people over 85 at this point (most of whom are obviously not working anyway!)

It was replaced with this: https://www.gov.uk/marriage-allowance

Which may be useful (but only if one person is earning under £12,500 and one over £12,500).