How much to charge for installing a ventilation unit?

I am a builder, who has installed ventilation units before, but always under someone else's company. I am now quoting for my first job as a sole trader of a very simple through the wall HR30W Vent Axia shoe box type heat recovery ventilation unit.
I have a few sparkies in mind to do the electrical side, and I can cut the hole in the wall and make good.

The only question is ball park figure. The client is in Sutton, and the unit is around £190. The job is to supply & install the unit through the solid brick wall, and connect up electrically to the mains via an RCD fused spur from the nearest twin socket, with a 4 way switch (ON/OFF and LO to HIGH speed). Trunking will be exposed.
I would imagine the hole in the wall 2-3hrs, and the electrical 2hrs. Plus time spent do quotation and organising everything.

Can someone give me a ball park total figure for all work, including the unit. I am not VAT registered so I don't need to add this on.

Thanks