Old Berkshire Boy
There are several places they could go & test there engines where the impact would not be so damaging on the river banks & the wildlife , evidently you havn't been to Strumpshaw Fen for a while to see the problem , I have spent over 40yrs around the broads & seen things get worse , by the sounds off your comment you have never seen a boat engine testing at Strumpshaw ,
I was at RSPB Strumpshaw Fen recently, about three weeks ago, and did walk along the riverbank, occasionally looking at passing navigation, which you'll see was very much part of my past career. Similar to yourself, watching stretches of the Thames similarly erode and detiorate in many ways for more years than I would wish. I'm sure that the Broads authority are well aware and have consultation meetings about this and many other matters including their duty to protect and safeguard it's heritage. I would be genuinely pleased to hear from you about the other suitable sites along with any environmental impact studies that relocation of said testing would bring.
All the best, Pat