It lacks the IR/EO sensor of the MQ-4C Triton, so it still fails in the identification of targets at sea.
This is true for the specific maritime upgrade that Dunne is referring to here, but at Farnborough the RAF was briefing that it is looking to introduce four enhanced capabilities onto the Sentinel platform:
A specific maritime function for the aircraft's radar system.
Options for long-range optics
Options for SIGINT
An enhanced airborne mission system.
The maritime function is especially seen as a quick win, given that this would largely be a software upgrade to the sensor, but that doesn't mean the Sentinel won't get an EO/IR capability also.
Then there is the almost meaningless sentence, “Additional sensors could be fitted to further boost the platform's maritime surveillance capability.”
Not quite so meaningless, given the above.
Crowsnest Merlins would do the radar detection Maritime job so much better in areas where long range and persistence is not required.
It's hard to think of a more inefficient way of doing maritime surveillance than with a helicopter.