I remember talking in 1979 with the pilot of the Tintagel Hunter, who was similarly damaged by one of the early seats. His ejection sequence was watched by a chap in a small fishing boat who had just retired after 30+ years with Martin Baker! He told me that he wished there had been a dial-down selector on the seat so that you didn’t get the full charge for a premeditated ejection.
That episode and Ray K’s (earlier?) Lightning ejection at Valley prompted the change to all FRCs that included winding in half aileron trim before stepping over the side.