There is further info on the accident on Paul Cox’s Christen Eagle II website
Christen Eagle II Aerobatic Biplane Sad, Sad News…Seething ‘Plane Crash
The two pilots flying in G-EGUL were both extremely experienced. From initial reports, this looks like a truly freak accident where G-EGUL, reported to be low on final approach to the runway, appears to have hit a tractor which was crop spraying the land adjacent to the threshold (most of the land at Seething surrounding the runway and taxiways is laid over to crops). The tractor driver thankfully escaped injury. I understand from a source at the scene that Ian Davies was PIC (Pilot in Command) so he would’ve been flying from the rear seat - obviously normal for an Eagle. He wanted some time in the Eagle for a magazine article he was writing “Buying a Christen Eagle II”. Looking at the wreckage, it’s amazing that anyone survived.