Simple loft extension? How much did you pay

[reren]

We are looking to do a very simple loft conversion and trying to get a sense of cost. We will create one room only without building out a dormer / mansard roof or putting in an en-suite. All we will be doing is putting veluxes into existing roof and a staircase. I've done a loft before and am familiar with the various costs (fire doors, smoke alarms, steels, insulation,etc) so I know it isnt necessarily cheap or straightforward even though its so simple - but I wondered if anyone had done anything similar recently and how much you paid?