I looked at 2014's Hunter display at Shoreham Airshow by the same aircraft:
https://www.youtube.com/watch?v=wrIzRdcSizM
Jump to 45:07 to 45:20 you will see the aircraft start the display coming in from the left of the crowd line, doing a roll and making a left turn away from the airport. From earlier part of the video, you can see that the crowd line is just between the grass runway and the airport buildings, approximately parallel to the A27 and facing Lancing College.
The aircraft goes around in a turn over the River Adur and approaches show centre (the airport crowd line) head on, pulls up and when the loop is almost completed, banks starboard and finishes flying past the crowd line level towards the west.
Contrast with this year's display as seen on
https://www.youtube.com/watch?v=PeSpNNxcVEg filmed from 50°50'50.10"N 0°17'34.10"W
https://www.youtube.com/watch?v=pvHplYmh2f8 filmed from 50°51'0.82"N 0°16'43.21"W
2014's display starts the same as this year's display where the aircraft did the same left to right flypast, roll and left turn to come around towards show centre head on. Whereas in 2014 it did a full loop along the north-south axis, this year it did a 1/4 clover starting along the north-south axis, 1/4 roll and then the rest of the loop and crash in the east-west axis . Assuming both years' display routines were planned to be the same, then we may suspect something went wrong, whether human or mechanical, that caused the routine to deviate at the initial quarter loop to turn into a clover.
Notice also that the flying this year seemed tardy, where the plane wasn't level while at the top of the loop. I can't help thinking why this year, the aircraft started the 1/4 clover climb at such a great distance from the airport's grass runway (where the crowd line was), when approximately abeam of Lancing College. They usually display much closer to the crowd line at airshows.