Dear Karen,
This isn't an answer to your question but as I work in education and have term time only workers, I wondered if you'd factored in shared parental pay to your maternity pay review? Given the long holiday periods that teachers are entitled to, our staff are using shared parental pay to curtail their maternity leave and technically return to work during the holidays on full pay, and then go back on shared parental leave during term time. It's perfectly legal, though clearly not the intention of the legislation. I wanted to mention it because this loophole is stopping us from enhancing our maternity pay as we had wanted to - because the practical impact is that our term time staff are able to get about 3 months of full pay using this process, as well as the SMP in our policy. Just worth bearing in mind when you're looking at the true future cost of any changes.
Thanks,
Nina