Overtime payments will affect the TD as it is additional income. I don't think it is possible to have regular overtime payments without passing some of this money into the TD. Still as long as you discuss this with your trustee and confirm what the rules are then you will know where you stand.

My partner who is on maternity leave just now, in theory, is as well becoming a full time mum for the duration of my TD because if she goes back to work, it will free up cash for the household and we will simply have to pay this over. Good and bad I suppose.