If a person applies for voluntary redundancy and it is accepted - would they also be entitled to 28 days pay in lieu of notice (as per the notice period required contractually) ??
OR
Do they forfeit their right to that 28 days pay in lieu of notice because their redundancy is voluntary rather than enforced ??
No they don't forfeit their right.
Some employers declaring redundancies will decide to let people go quickly and pay money in lieu of notice, but there's no obligation on them.
An employee can be asked to work out the notice period in both voluntary or enforced situations.
It isn't a fixed 28 days either - it depends on your contract and how long you have worked there.