Employment got before agreed term expired

Can anyone tell me what is the likely scenario for the following:
A person is given notice of redundancy, redundancy package is sorted, an agreed term to stay on is fixed to train. What if you find a job within this time elsewhere, are you still entitled to the agreed redundancy package or are there laws for this?

Why are you being trained if your being made redundant

Not being trained in but training other people as to what i do for when i am gone!!

As regards statutory redundancy, you serve an RP6 on the employer requesting that you can leave early - it is discretionary as to whether or not the employer consents to you leaving early and still pays your statutory. If they refuse you can take a case to the EAT and they will award statutory if they consider your reason for leaving early was reasonable. See
Unless there is some contractual or written agreement to the contrary the employer is probably under no obligation to pay any ex gratia.
Suggest you ask them what happens if you find a job..