TR4A seat belt mounting

[John Middlesworth <jape@email.unc.edu>]

I want to put 3-point belts in my 4A but I'm not sure which is the proper
place to mount the shoulder belt.  I've seen on top of the wheel arch and
on the side of it (on TR6s).  Questions:
1. Is either of these positions more original than the other?  (Was such
an option ever offered?)
2. Will I need additional reinforcements to hold the mounting bolt besides
the sizeable washer that comes with it?

John Paul Middlesworth
1966 TR4A