A few years ago my company was acquired and at that point I had been in the business for 10 years. All holiday and other benefits were transferred across but only a few months ago I realised that my maternity package is not as I had expected. My previous company had a policy which rewarded loyal employees well and as a result I have remained loyal to the business. I am shocked to discover that my maternity package is now the current employers scheme which is significantly less. I was never informed of this and I do believe that had I been notified I could have made the necessary steps to leave and find another job prior to starting a family.
I expect that the acquisition will be covered by the TUPE legislation (unless it was done by way of share sale). This means that you transfer to the new company on your existing terms and conditions and they cannot be “harmonised” with the new company’s terms unless the reason is not because of the transfer.
In any case, you should be consulted before any changes are made to your contractual terms. You cannot be deemed to have accepted any contractual variation if you did not know about it.
I suggest that you raise the issue with HR and point out that you should receive the maternity benefits associated with your contract, i.e. the “old” employer’s scheme. If you do not, you may have a claim for breach of contract or unlawful deduction from wages.