Personal allowance reduction on bonus payment

[Mortgageadviceda]

I’m hoping someone can advise please. My salary is just under £100K. I’ve found out that my company may be paying two bonuses this year. One in July and one in August. If paid this could be up to £35k. It could also be much less.

At the moment my tax code allows me to receive my full personal allowance tax free but if I receive the bonuses this will take me over the threshold and I will lose some / all of my personal allowance and owe tax on this.

Ideally I want to stay on my normal tax code with my full personal allowance and if the bonuses are paid, keep back the additional tax I will owe and pay it one sum at the end of the tax year. I would rather do it this way way than HMRC change my tax code to recover this tax and then each month, when I get my normal wage, pay higher tax as my normal monthly pay will decrease as I need my normal salary to cover all my outgoings (mortgage, childcare etc).

The question I have is is this possible and if so how do I make this happen and stop HMRC changing my code when the bonuses are paid?

Do I need to complete a self assessment tax return at the end of the year to cover the tax owed?

Ps not trying to avoid 60% tax trap as paying max into pension. This is purely about how to keep my personal allowance tax code and pay tax bill separately at end of the year