Southend Air Shows – Late May Bank Holidays

I have unearthed a strip of film which has negatives of Bell 206Bs G-STOX and G-HMPH giving ‘joy rides’ from Southend sea front, next to what was then the Brent Walker Leisure Centre (it still exists, west of the pier, and is the focal point for the annual air show over the late May Bank Holiday each year). Also parked in the same area was Gazelle ZB625:N. I remember shooting the film, but it is not in my note book, so can anyone out there please tell me which year it was? ‘MPH was not registered until April 1989, so it must have been May 1989 or 1990 or ….. Thanks in anticipation.