EFE gear selector switch is about £60.. from robinsons or fowlers
2nd hand Garry Hurd or Chris Tombleson should be able to help
its used on a few models trawl the part no on a well known site
I fitted a set to this years ago...no heat just used some wooden wedges to spread 1 & 2 and the same on 3 & 4 and i used 2 suzuki gaskets in each port as the thou headers are a smaller bore and prone to blowing
i would add that using the correct clutch lever and perch makes a big difference a longer cable "faired efe is longest" can also help dept on what handlebars your using ...