Just found out about these three evenings being held in June, July and August. Might be of interest to those of you in the Hants, Dorset, Wiltshire, Sussex area etc.
https://www.beaulieu.co.uk/events/classic-grille-evening-20-july/
The 20th July event will be for bikes of all ages, with a free ride in (needs to be booked online but there's no charge), plus reduced price admission to the Museum (for those that want to go in), food and drink, visiting motorcycle dealers and a start up of Mike Hailwood's 1961 TT Winning Honda RC162.
At present it looks like you can only book the 22nd June event but that might be worth a look anyway and I'm told bikes will be welcome to ride in on that day as well as classic cars, should you be interested in four wheels as well as two. They're taking bookings for the July event after the 22 June.