Dometic doom

KENTUCKY

Hello, I have recently bought my first motorhome which is equipped with a Dometic TEC29 generator. This has now failed to function properly and I suspected the problem could be the fuel pump (£114 from leisureshopdirect - approx.£10 elsewhwere) or the caburetor
 (£808 from leisureshopdirect - approx.£10 - £30 elsewhwere - also I can buy a complete new GX160 honda engine approx £400 elsewhere) or the inverter (replacement cost £880!! have not bothered to find alternative). Dometic UK have been of little
or no use other than directing me to leisureshopdirect. Is this real or am I missing something?