Thank you…
I think you might be right about the screen. I ended up using double sided tape to hold the screen so it’s a little more proud than would have been preferable.
One possible solution which I rather liked was a CNC cut brass plate right across the front with the switches set in to and the screen recessed …
Just really glad to have ‘finished’ ( Yeah right) the hardware side.
Now just setting up the audio in and out levels using a zynth on the input and one on the output… 
and the sine wave generator engine, which sadly doesn’t have a left/right mute which would be really helpful. I’m reading up on LV2 to see if I could alter it suitably to add them or build a test tone generator from scratch…
Given the complexities of stereo in with mono defeat on one channel and the cross wired mono outputs that should provide stereo if two jacks plugged in and a mixed mono if only one used ( nicked from the alpha juno 2 circuit ) .
However the bypass switch is helping a lot with the line up process and it’s status is now indicated by the colour of the LED on the front panel. Red for zynth in circuit, green or off for bypassed… 
IT’s mostly sitting and soak testing at the moment.
It’s now got a badge …!