We did Dover-Calais as the increased costs of Portsmouth crossings did not justify the time savings to us. We were in the car, so the extra time sitting down was not so much of an issue either. Formule1 are fun places I think and yes, cheap and cheerful for sure.
One thing Messie if you decide to go via Orleans, try to avoid Paris at peak times or avoid it altogether. The Peripherique has some suicidal bikers, more so than than that London IMO. If you do end up there, keep your eyes peeled