you will have to check the terms and conditions of your policy to find out for sure - or ring them and ask them.
As to benefits, you wont be able to get any means tested ones, after all you will have means! redundancy pay is to compensate you for not being able to earn, as are benefits, so i would imagine you will have to use up the redundancy pay first Plus, looking on the bright side you could easily find another job and not need to apply at all. Yu will probably be able to get contributios based jsa for up to 6 months if you have paid enough NI