Taking a sprinter or crafter, 1500 miles approximately there and back…working on an average 25mpg/ £6 a gallon £360. Ive no idea about Ferry or motorway charges…

Aprox €140 in tolls last time i drove a few years ago & £110 on tunnel

The tolls go through as a high vehicle so extra – still worth it over the crap roads that are not toll.
Ferry/Tunnel just go through to booking and it will tell you, you just need to cancel at the end of the process. Tunnel is faster and easier.
Avoid Paris and either start early and take your time or late tunnel over kip on the other side and get going. Driving through the night sounds cool and all the hard men do it but your body is not used to being awake at those times and you are much more susceptible to lapses of concentration or micro sleeps in the early hours.

You’d be looking about £120 each way for Tunnel, £100 for ferry each way. Fuel, as you’ve said £300-£400 and tolls will be approx £100.

The €140/ £100 in tolls is that both ways?