Thanks chaps.
I ended up speaking with a few companies, ranging from £300 to £55.
I opted in the end to go with the PHL Group:
Platinum Holdings Limited - Ronaldsway Airport Isle of Man
£25 for handling, £18 landing and £4 over night parking.
They bring a hire car air side for you, fuel at £1.62p/l + VAT, have a mobile ops centre with weather / flight planning services up to you departing
£55 is pretty good value for than level of service. Not much more than Manx flyers.