Thanks for the replies everyone
It seems that anything from 10 to 30 seconds is the norm, depending on the amount remaining in the gas canister.... hmmmm... not what I wanted to hear, really!
Are you sitting comfortably? Then I'll begin:
First steaming took about 5 seconds to fill before the liquid spurted out. Loco ran for a full 20 mins.
Second steaming, same again (about a 5 second fill before it spurted) but this time it barley heated the water before the gas pressure dropped and the tank was empty
Third steaming (new gas canister in case old one was playing up), it took a good 20 - 30 seconds to fill and I got the full steaming time.
The 30 second fill time worked for
every subsequent steaming until last night...
I put partly used canister to gas valve, pressed down and after 5 seconds got the spurting again. I thought 'Hmm, that's not filled properly, I'll open the valve, let it empty and do it again'. I then tried again - same results! Now I'm thinking that the valve has a problem but this time I decided not to waste the gas and carried on and lit it to see how long it would be before it ran out.
Guess what?
Yep, I got the full 20 minute run out of it.
After it cooled down I unscrewed the valve and had a look at the needle but nothing seems amiss. My next step would be to take the actual filler valve off and have a look for any swarf/dirt clogging the mechanism but I'd like to know if it's just a case of unscrewing the top?
The loco is still under warranty but I'd like to fix it myself to save all the hassle of packaging it up and sending it back.
Any help gratefully received!