The Bown is made to the standard autocycle recipe.
98cc Villiers engine. In this case the single speed 2F engine which dates it in the late 40's early 50's.
Webb forks. Easiest place for info on care and adjustment is a Velocette handbook as Velos used Webbs for year until 1946-7 or so. All Webbs are built in a similar fashion regardless of size.
Wheels are usually British Hub Co. Just oversize bicycle wheels and the rest is just heavy bicycle.
Top speed about 30-32mph but feels like a lot more.
Tank transfers available from either the VMCC or Classic Transfers.
There is a hardcore of enthusiasts for this type of machine and they run some fun events.
All the best, Bob