Your friendly local Spidermen BSA owners (I'm one of 'em) have a last Sunday of the month ride out from the Super Sausage cafe. It's on the A5 at Potterspury, between Towcester and Milton Keynes. The postcode is NN12 7QD.
You can either get there in time to have breakfast and a look at the bikes, or have a little longer in bed but still get there in good time for the run, which leaves at 10:30 am.
Other makes are accepted. This includes my 1981 Yamaha, which other BSA men tell me is a modern bike... Meanwhile, the M33 will be back on the road soon, honest.