careful with your assumptions
FR24 shows groundspeed
A flight flown at Vne in IAS terms can give a completely different TAS or Groundspeed value depending on local ambient winds and density altitude.
There is no credible reason why an aircraft should be operating for certification purposes at Vne+40 kts, but in any case the report quoted states that they were approaching Vne, so the speeds quoted are meaningless or misleading.
Nobody here has the info required to work out what happened, so it would be better to stay quiet on any reasons why the aircraft and crew were lost, both on this programme and on the AW609 (but then again this is a rumour site so anything stated here should be taken with a huge dose of salt).
Thoughts from the southwest of the UK are of course with the crews families and the Bell employees involved.
DM