I think im right in saying that in order to commence training for issue of your first Type Rating you must be in possession of a valid ME/IR.
So yes you will need to renew.
As for the mention of a type rating for a seneca, you have a MEP class rating not type rating. The MEP class rating is not type specific hence CLASS rating.
Hope this helps
Nick
PS your ME/IR is for SPA - Single Pilot Aeroplanes, your type rating will give you a new ME/IR for MPA - Multi Pilot Aeroplanes. They are different and will need revalidating seperatly.