NEC ECC: ECI (NEC3) for an Option A main Works

Dear Team members, some assistance / your thoughts please, regarding the ECI (NEC3) and a proposed main works contract of NEC3 (Option A).

I've got a preferred contractor that's signed up to the NEC3 and Client's T&C's from a framework. The Client's FBC (and therefore full funding) won't be approved for another 2 months at least, possibly 3months)
 
We're looking to progress some early design works in the interim to mitigate delays to the final delivery / Completion. Rather than enter into a separate contract (PSC) for the Early works, I thought we might try using the ECI, but am aware that it is really for Opt C or E.
 
Can the ECI be used with a minimum of bother (proposed Contractor is happy with PSC / ECI / PCSA) either way, but client would prefer one contract - i.e. (ECI as Stage 1) and progress to Stage 2 (Main Works) if funding / approval all goes ahead as anticipated? (Obviously with the option not to proceed if the FBC is rejected - albeit a very remote chance / possibility? )

Can anyone assist with some direction / if it's been done before please?

We could go ahead with a "run of the mill" PCSA, but I was sort of hoping to use the ECI?

Assistance much appreciated.

#ECI #PCSA #EarlyDesign