Calculating redundancy pay..

I am going through the process of possibly being made redundant, so I am trying to work out what I would be entitled to and I am a bit confused on working out weekly pay..

I am salaried and am paid monthly - every month I do some overtime, so my pay does fluctuate and we have just been paid a bonus.

The gov website says that “If your pay varies or you’re not paid weekly, you have to use a 12-week period for working it out”

The 12-week period
You can work out your weekly pay by getting an average figure for a 12-week period. The particular 12 weeks you use varies depending on what you’re calculating your pay for.
Redundancy
Use the 12-week period leading up to the day you got your redundancy notice to work out your pay during the time you take off for job-hunting if you’re being made redundant.
Notice pay
Use the 12-weeks leading up to the first day of the notice period to work out what your notice pay should be.

So am I correct in thinking that I should take my last three payslips before my redundancy date, add the Bonus, Overtime and the gross pay and then calculate the average? That just seems wrong because this amount would be above my normal pay.


Thanks