Late 401 Fuel Tank

[Pete B]

I am currently renovating a 1953 401. On removing the fuel tank I was surprised to find it was of steel not aluminium as I expected. It didn't seem very well made in so much as it was partially welded and partially brazed and of course heavy, however it did the job and didn't leak. Did Bristol ever fit steel tanks, more importantly does anyone have a spare alloy tank, or know where one could be obtained?