SMP basic rate is going up from £151.97 to £156.66 from April! I had no idea, I've been trying get myself sorted for starting my mat leave in April (I'm a bookkeeper and run payroll for one of my jobs) and when I submitted the claim to get advance payment for my employer a couple of weeks ago even the HMRC's own claim form was still using the old rates. They then sent it back to me asking to submit again with new rates, but my other employer (who I don't do payroll for) had submitted their claim only a week before and had the rebate through with old rates even though my maternity leave starts in the new tax year.
So if your maternity leave starts soon, or is ongoing until next tax year, might be worth checking with HR about your payments!