It depends what you mean, if this is a redeployment into an "alternative suitable role" then yes, it's normal and your legal right to have a trial period (this also works for the business to make sure you're actually suitable for the role) which is 4 weeks, it can be extended if necessary such as further training needed. Let's assume, for the rest of this, that it is a 4 week trial (or probation as you've mentioned) period.
If you leave before or at the end of the 4 week (or agreed) trial period, or your employer terminates the contract due, and it is due to the role not being suitable ^, then you'll be switched back to being redundancy and qualify for your payout. If you stay longer than 4 weeks, outside of an extension agreement, then you've effectively accepted the job and won't be entitled to redundancy pay if you choose to leave.
^ Suitable being down to differences between the old and new contract being far out of line. If you choose to not take on the role, during a trial, and it is a suitable one then you might end up not getting a payment because you have "unreasonably refused an alternative suitable role" There are exceptions to this, it is down to negotiation with each individual business.
Sources: UK Gov, and trade union experience