OK, I've managed to solder-up and test one of my PCBs and it works a treat. I am well happy because I have made it so much smaller than I've ever managed on veroboard.
**broken link removed**
What did I learn?
Export Fritzing files as "shareable" or just go for Gerbers. Silkscreen is worth having - I was lucky, I didn't ask for it, but I got it from pcb-pool.com by mistake - and, therefore, for free. The prongs of my headers did not fit into the PCB board holes, so I had to do some drilling. I'll make the holes for headers slightly larger next time. Also, the area taken up in Fritzing by the "Screw Terminal" is somewhat larger than my actual headers, so I would address that in the next design and save some extra space.
Sure, it's simple... but I genuinely figure I've made good progress now. I've learned how to program PICs, how to code in a new language, how to assemble things on breadboard, how to put things on veroboard (inc. how to solder) and, finally, how to take something through to a form of manufacture... it all feels very "end-to-end".
Dragons' Den here I come!