Hi
I have been in a similar situation to you.
Last year, I went through a redundancy process, 90 day consultation etc (actually in the end decided to opt for voluntary redundancy as the money was excellent and would have paid for several private IVF treatments but was turned down

)
Although my job is now safe, I realised I could actually get significantly more money in the market place and had to weigh up whether to seriously start looking and applying for other jobs or to stay put.
I came to the decision to remain where I was on the basis that most companies seems to have a minimum employment term before you are eligible for their full maternity package and as the main earner, dropping to SMP was simply not an option as having had an expensive wedding less than 12 months ago, we have very little savings to fall back on.
Also another consideration was that I am much more likely to be able to work flexible/part time hours in my current job whereas in a new job, you can't guarantee the same flexibility.
Hope the above helps and gives you something to think about in your current situation. I think a lot depends on your personal circumstances and whats right for you and your family as for me, it's not just about the maternity pay but also part time flexible hours when i do return to work.