As its commercial the defender can still go for sva. I have a 6 wheel cummins landrover and im trying to go to 4.3t hgv at the moment having submitted brake calculations.
A friend of mine built the 6x6 discovery which was in lrm a few months back, being a passenger ,not commercial he had to submit to a iva test which the car has to comply with 2010 regs it failed on mudflaps, roof gutter, centre box having exposed hinge even the standard 98 disco seats have failed on rear padding!!!! pattern part front grill,being not genuine they even pulled down the dash and condemed the factory standard wiring!!!!!!!!!!
Defender and iva ......wouldnt like to try