There's a purveyor of plastics near by and I dropped in looking for small squares of perspex(tm) that would suit my application. I was amazed to see that they had a wall display full of suitable squares:
Of course they are samples that are given out to architects. The lady was a little puzzled when I asked how much they are, I got the impression she'd have given me a few for free but asked for a few dollars for ten.
Here's what I made:
And here's the back:
I clearly need to learn how to drill straight and proper strain relief for the dipole wires but this is perfect for my "quickie" temporary antennas.