Yes. You can take holiday during your notice period, subject to the same approval rules that apply at any other time. Many employers actively encourage (or require) you to use accrued holiday during the notice period rather than be paid out for it at the end. Whether you can take a specific week off is still a matter of your manager's sign-off, not an automatic right.
Holiday entitlement keeps accruing during your notice period at the same rate it always did. If you have unused days at the point of resignation, plus the days that will accrue during the notice period itself, you have two options: take the time off, or have it paid out at the end. Which option applies often depends on your contract and your employer's preference rather than yours.
Most contracts include a clause that lets the employer require you to use accrued holiday during notice. The wording is usually along the lines of 'the company may direct you to take any accrued holiday during your notice period.' If yours has that clause, the employer can effectively force the issue. This is often used to shorten the working portion of your notice without paying PILON, particularly when there isn't much left to hand over.
Asking for holiday during notice works the same as it always did. Submit the request through the normal process; the manager either approves or declines. Reasonable refusals are still allowed (peak periods, handover overlap, sickness coverage). Unreasonable refusals are usually grounds for a conversation rather than a tribunal, but if a manager is blocking all leave specifically because you're leaving, that's worth flagging.
If your employer refuses to let you take accrued leave during notice and won't agree to pay it out, you can technically end up worse off. The Working Time Regulations require statutory holiday to be paid out on termination, so any statutory entitlement (5.6 weeks per year, pro-rated) must be paid. Contractual entitlement above the statutory minimum can be lost if the contract says so and you didn't take it. Check the policy.
The maths is straightforward if you do choose to take the time. Days worked plus days on holiday plus weekends still add up to the end of the notice period. If you have ten unused holiday days at the start of a one-month notice period, taking all of them roughly halves your in-office time. Holiday days are normal paid days as far as your salary is concerned; you stay on payroll and your employment doesn't end any earlier.
Bank holidays during your notice period work however they always have for your role. If your contract says bank holidays come out of your annual entitlement, you'll use a day. If they're separate, they're separate. If you're on a working day rota that covers bank holidays, you work them as normal. None of this changes because you're on notice.
What does change in practice is everyone's bandwidth. Asking for the last two weeks of a four-week notice off as holiday is a big ask if you've got an unfinished handover. Managers tend to be flexible about shorter blocks at the start (use a week now, then handover) and resistant to anything that compresses the actual transition. If you've got significant accrued leave, propose a plan rather than waiting for a fight.
General information about UK employment law. For your specific situation, contact ACAS or an employment-law solicitor.