If your employer makes a payment in lieu of (i.e. instead of) your notice, rather than requiring you to work it, this payment should be based on your contractual rate of pay. What is included in the payment will depend on your contract of employment. A payment in lieu of notice would not normally include overtime payments, shift premiums and other bonuses that depend on you working.
The period of paid notice you are entitled to will be your statutory period of notice or the period of notice set out in your contract, whichever is the longer. If you are on reduced pay because you are absent due to sickness, or because you are on maternity, adoption or shared parental leave, where the employer gives you statutory notice, you are entitled to full pay while working out your notice, even if you have already used up all your entitlement to paid leave.
The rules are different if you are entitled to notice that is a week (or more) longer than the statutory period of notice. Here, if you are off work during your notice period, your employer only has to pay whatever statutory or contractual sick pay or maternity, adoption or shared parental pay you are entitled to. If you have already used up your whole entitlement, your employer may not have to pay you anything during your notice.
Any employee made redundant during the coronavirus pandemic after being furloughed under the Coronavirus Job Retention Scheme must have their notice pay and statutory redundancy pay (subject to the normal cap on a week’s pay) calculated based on their normal ‘pre-furlough’ wages.