Hi Tony
You can try the AAF museum shop for Tamiya spares, I'm told the lady in charge is very helpful -
http://www.aaftankmuseum.com/RC-Tank-Parts.htm. I think Andy was hoping to get into Tamiya spares as well...?
Right, I've had a scrounge around - I do have a mantlet, but no barrel (which would be wrong anyway) and I've robbed the elevation motor for my T34/76...

Now all I need to do is find all the screws...

10 quid should cover P&P (hopefully)
For 25 euro's I'd still recommend Peter's gun and mantlet kit, its soooo much better looking that the HL... He also does the single peice comanders hatch as well.
And plans for the turret schurzen are posted in my member space
Cheer's
Mart