Webasto dual top

Tried this for the first time today afater purchasing a auto sleeper cotswold 2010, Everthing seems ok on the display but not getting any hot water, My question is... Does the heater provide instant hot water or does it need to heat up first, Thanks

Virtually certain it will never be instant, in more or less any MH, it would take oodles of power to add that amount of energy to heat useable quantities of hot water.
So, no it isn't instant, don't know what system yours has (probably some form of Truma, combined hot water and ducted air heating) allow 30 mins to an hour for the (probably 9 litre) hot tank to be heated to 60c. I'm also assuming that water is coming out of the hot tap, even if cold water, if so, then the hot tank is full, so just a matter of adding the heat.

I presume your duel top is a diesel  heater  if so the hot  water is heated very quickly , check the space heater is working,if so then try the hot  water

Found a bit of info duel, top   20  to  60  minutes  for hot water  .I had a thermo top  c that was faster.