Progress so far...

The rest of it came together fairly quickly. Apart from an annoying coolant leak from the thermostat gasket , shame I didn't test it before mounting the down pipes.
The paint isn't perfect but it's good enough for me. I went with gold stripes on black. I just copied some pictures of other bikes, using the design I liked the best.
Considering how the tail piece started, it was quite satisfying.
 

I take my hat off to you - I think your bike looks fantastic.   Those mufflers - similar shape to the originals , but smaller.  What make are they? What is the sound like?
Hiw does the bike perform?  You had some concerns over the cylinders ; is all ok?

Very nice job. Congrats.

Thanks! I'm fairly happy with the way it looks now. I hate to admit it but I sold my original mufflers to help fund the rest of the bike. They go for silly money these days but I wasn't greedy. The mufflers on the bike are just cheap Chinese universal mufflers from Ebay, probably 50 or £60 for the pair from memory. I like them as I always felt the originals were just a bit too big. These sound nice, just like the originals except a little louder.

The bike starts well. I didn't even have to use any easy start. It fired up immediately. However I can't seem to get the bike to idle, plus It still pops sometimes at very low rpm, from the carbs as it did before. I was hoping new and clean pilot jets would have cured that.  If I turn the idle screw up it just revs high and won't come back down quickly. I set the ignition timing as in the manual.
It does Idle if I keep the choke on a little. Maybe my mixture screws need opening up? But here's a pic of the plugs after a 30ish km first ride.

I tweeked the mixture a little richer on 5 and 6 for the second ride, I forgot to take a pic of the plugs for that, but none had any white this time.

Apart from that it runs well and pulls smooth and hard.  I have a feeling it still runs a bit hot but I'll know for sure when I ride a bit more

Your idling issue is typical of blocked idle circuit passages and the best resolve for this is to pick up one of Scotch's "Cleaning Tools" He put a lot of thought and effort into the design and it works a treat. Send him a PM with your name and mailing address so he can quote you a price including shipping. You won't regret it.

Thanks Kawboy. Ah ok...Funnily enough I do have one of Scotch's excellent cleaning tools and I did use it to clean the carbs. I must have missed something then.  .  
I used carb cleaner as I couldn't find the recommended Lacquer thinner,  I'm in France, and every place I asked for it, I was given a funny look and a French shoulder shrug, followed by a shake of the head...as though I just asked them for a tin of "Dragon's sperm" or something.

This'll be the 3rd time the carbs will come off for cleaning...I'm glad I fitted those pod filters now.