Thank you for your comments, guys - much appreciated!
Hi, Silver, Yes, quite right, you can see the brass. Fortunately it looks to be part of the design when you see it in the flesh (strewth, it's that flesh thing again!). Despite the amount of times I swear I'm gonna paint the tubes I only remember to do it once I've applied the glue!!! Must be an age thing - I must keep taking the cod liver oil!
Bob.