TOFO,
IMHO, the next SDSR (15 or possibly 16?) is massively important but not critical. What do I mean by that? - well, lots of staffwork has gone on behind the scenes to support the need for an MMA (MPA), with some recent events that clearly justify the requirement. The SEEDCORN programme, which includes MPA SQEP/SME's in key positions in the UK, as well as the operating aircrew overseas remains perfectly positioned to re-generate the capability, if a positive decision is made in the next 12 months.
However, I think its pretty certain if whoever is in power makes a 'no' decision, then SEEDCORN will be wrapped up in short order. Personally, if this is the case, I think some government down the line will get back in the game - maybe SDSR 20 or 25 but obviously, we will be starting from scratch. Hence my view that it wouldn't be critical to delay another 5 or 10 years but we would miss a massive trick - and as you well know, it could take a decade or more after IOC for maritime aircrew generated from scratch to get anywhere close to the 'lost' experience.
Individuals like me who bang the table justifying the need for an MPA aren't stuck in a Nimrod time warp. All off us accept that is history and have moved on. We make a noise because we believe the UK badly needs an MPA full stop.
No getting away from the financial reality though, so despite many of us being optimistic, it really is a big unknown....