I got hold of some 50mm wide black sports tape (Kinesiology tape) and tried it on my new A pillar seal last night. It seems to work extremely well, slides beautifully, removal all the resistance and binding and looks just right. The adhesive they use on this type of tape might be a concern as it is designed to come off without ripping off your skin, but it is also designed to stick to sweaty skin, so might be OK.
I will try scrubbing the seal down well with Paint Prep and see just how well I can get the adhesive to stick. I will do some water tests next weekend when I have time.
So, in conclusion the tape idea seems a really good one, we just need to find one that stick well enough, is waterproof enough and is colourfast.
Thanks for all the suggestions.
Jeff