I believe Richards son is now making the chairs. They have a web page but there's very little in the way of information on the page, sadly.
I watched as Richard made the sidecar my ex missus has under her house, back in 1976, my guardian was having it made and we spent 2 days with Richard and his family, staying at Richard's place in Blackheath. He was the nicest of gentlemen and his son was very involved in the building of the chair in their little factory.
Richard was an amazing engineer and used to do all of the original radiators for the very old cars, radiators and front grilles. He was an amazing craftsman and people came from all around Australia in the day to have Richard replicate the items.
A friend (same friend who owns the K100LT I'm doing the panniers for) has an ST1100 Honda with a DJP or the other heavy glass unit I can't remember the name of (Ron Hurdiss?), wait, that may be the DJP or the HRD, I can't remember but I knew Ron back in the day, he was a Penrith local and I grew up in Penrith (he was/is older than me).
I know I can't get into the things with long legs and that big dash panel, that's where I thought the Westcar was supreme, plus the lack of weight in the steel construction.
I have a photo here of my old Honda 250 with Westcar, somewhere. I grew up learning to ride chairs when I was around 12 and have loved them ever since. I'm now 61 and a bit (actually, that's 34 and a bit, I've just had a very hard life, lol).