Melchie,
MQ-9, BAMS, ATR 72, Sentinel, E3D etc may be tweakable for an acceptable level of ASuW capability. However, non of the above can do the primary role of an MPA which is ASW.
The paperwork is in place to support the need to regain a national MPA capability but non of us really have a clue how the election/funding/SDSR 15 will pan out.
Fingers crossed for a bright MPA future!