Unique half-cab Dennis F12 appliance FXG300 originally supplied to Middlesbrough FB, seen at Shildon museum on July 10th 2010. (Ken Reid)

Ian Moore writes ... This was long thought to have been the sole Dennis F13, because unlike an F12 it has (amongst other things) a 400 gallon tank. The F12 of course only carried 100 gallons and was either a P or PE. This one was a WrT. However, FXG300 is in fact plated as an F12, chassis number 4185.

Yes, it was originally supplied open, and the fibre glass roof (secured by four wing nuts) was fitted later, being constructed by a Kent based company.