Given the choice: a combination of 20-odd new Chinooks, plus at least 3 Sqns worth of AW149s.
The Chinooks speak for themselves - their utility for air assaults and as heavy transports has been proven conclusively on HERRICK.
The AW149s would presumably operate in pairs in high-threat environments (thus reducing the burden on AH as escorts), they're ideally sized for light transport / patrol inserts / EVCPs / Admin tasking etc, and they're comparatively small. Which, in itself, has advantages - being able to use smaller HLSs and being more difficult to hit, to name but 2....