The cutaway engines sound interesting and must have taken a while to complete.
Regarding the Pioneer P12 chainsaw…I have very little knowledge of chainsaws but I have a bit of printed info that briefly mentions Pioneer. Unfortunately, I cannot tell if it’s a rare model or not, but does it run and work or is it past repair?
Advertising appeared around 1981 including for the P12, I haven’t found an earlier P12 model. There was also a P12S model at the same time, it was listed as having a 35cc engine, 30.5cm bar, and a safety chain brake.
Danarm Ltd, Stroud, Gloucestershire were involved with Pioneer chainsaws in the UK and listed many models of Danarm and Pioneer models in the 1970s and ’80s.