With both Spectrum's working I decided on a few upgrades before calling it a day. Both of the cover plates are beyond fixing so I decided to buy replacements. The keyboard membrane on the Issue 4 also decided to give-up during the final stages and needed replacing. Both of these were easy to fit and only took a few minutes.
I decided to upgrade both with switched power regulators. These are much more efficient and remove the need for the heat-sink. Spectrum's are well known for getting warm so anything you can do to reduce this will help future-proofing.
With that done I declared them both finished, don't they look good :)