The LGW/PLH & NQY operation on the dash8 was for a few years quite profitable.
A number of factors changed this situation without any fiddling of the books : -
1/Flybe introduced a 3 times daily service on NQY/LGW with almost identical timings to WOW service . Decent load factors were maintained but only at the expense of yield and profitability.
2/The general downturn in the UK economy had a negative impact.
3/Switch of longhaul routes from LGW to LHR reduced connecting potential.
4/Probably the final nail , was Gatwick airports change in pricing strategy
Aimed at discouraging operators of small aircraft . This meant a sizeable proportion of seats had to be sold just to pay for landing fees and leaving little room to make any profit .