its the Pump assembly- for the fuel burning heater, good diagram (
http://www.rimmerbros.co.uk/Item--i-GRID001590) and its located just in front of the diesel tank on the tourer model on the right hand side. yeah £180 is a bit steep, might have ago with a tube of araldite for the time being.
have contacted local breaker, ill be interested to see what he comes back with