How much did you pay for each of the ferries?
I might have the opportunity to ride back to the UK from the South of france later this year. I'll use either the St Malo - Portsmouth or the Roscoff - Plymouth ferry and then take the train to Newcastle.
Roscoff - plymouth seems to make more sense as I can then take a direct train rather have all the faff of changing in London.
Hi Joe
The outbound sailing (Portsmouth to St Malo, which leaves the UK around 8pm at night and arrives c. 12 hours later in France) was £50, but I added a 2-berth inside cabin for £55 (i.e. total £105). You don't need to pay extra for your bike, but you do need to book it in advance. I booked in early January for a trip starting at the end of March.
The return sailing (Roscoff to Plymouth, leaving around 17:30 and arriving around 21:30) was £44 and again I added a 2-berth inside cabin for £21 (i.e. total 65). Making the total ferry costs for this trip £170. I had to pay £35 upon booking with the remainder deducted from my card about 6 weeks in advance.
I ended having the cabin all to myself on both journeys. It was worth the shower, proper rest/sleep time, dedicated charging points for Garmin, lights etc and space to dry your gear. You could also pay something like £5 or £7 to have a shower elsewhere on the boat.
Bike parking on board is pretty good. Embarking/checking in at Portsmouth Ferry terminal is a nightmare (you are not allowed in the terminal building and we had to wait in the wind and rain until the very last car had boarded the ship). At Roscoff it was all a lot smoother and more comfortable. Both times cyclists were allowed to disembark first however.
I paid £42 for a B&B in Plymouth before cycling the 400k back to London the next day.