syphon as much fuel out of tank as you can .
fill with diesel again .
if engine did not stop running when it had petrol in it you may be ok again
once youve put diesel in .
60 litres is a lot of petrol in a landrover diesel tank , especially if its a
90 defender ,almost a full tank of petrol , but perhaps being winter time you
may be lucky .
the petrol/diesel mix will make the injector pump run dry ,no lubrication to
pump , but if it isnt for too long then you may be lucky and find no real
damage caused .
you can run 50/50% mix of kerosene/diesel in winter [mercedes ML270 will run
this ok ] if its very cold .
petrol is much thinnner than kerosene and will have more effect on the
viscosity of the fuel , and of course the petrol has no lubricating qualities
at all .
if you are really stuck and have to drive the vehicle home , you can put
motorcycle 2 stroke oil in the petrol to thicken it , but i dont know how much
you would use .
perhaps 2 litres would work for you in emergency situation .