Via Alliance Agents Facebook Page:

Sadly, due to his health, Dave Prowse will be retiring at the end of the year. His family have asked that there are no further convention bookings made.
We will be working remaining bookings that are easy for us to get to, however there are likely to be a number of cancellations.
These are the wishes of Dave’s family, so I ask that people are respectful of this and understand when these cancellations have to be made.
We will not be accepting any further appearance inquiries!
You will all know that Dave has been a great friend for me for many years. It’s sad that his time attending events is coming to and end, but his health and well being must come first.