Overnight ferry help

[Kittkats]

I may have left booking a summer holiday too late, but was waiting for health issues to stabilise. We need an overnight ferry to France and back in the last 2 weeks of august. There has to be a cabin to sleep (health reasons again!) Outbound is fine, but coming back ferries are daytime only from st malo. What other routes travel overnight from France to UK?
I figured if I know ferry availability I can book accommodation around that.

Roscoff to Plymouth

The ferry coming back from St Malo still has cabins. You can book them and sleep during the day.

Yes, that’s probably plan B. Not sure if DH would be able to due to timing of medication though.

Dieppe to newhaven maybe? Less known route, depends if port locations suit you but you might be able to stay a night nearby in a hotel and then take a daytime crossing. Although a short night time crossing they also let you on early so you get a night’s sleep but a bit short

Dieppe newhaven? I hate the overnight as it’s only 4 hours and I feel jet lagged if I get evicted at 4am. For that reason (and cost) we usually do Chunnel or Dover/calais. Dunkerque is similar, but tends to be a lot less busy. Not good for overnight as o my 2 hours.

This is the Brittany Ferries timetable page. Click on a route you're interested in, then on the route page click on 'Calendar' towards the top left.

https://www.brittany-ferries.co.uk/ferry-routes/planning/timetables

Caen to Portsmouth has overnight sailings every night in August, for instance.

Caen has the advantage of being on the main road network.

If there are only two of you, you may find you'll have to book a four berth cabin - any two berth cabins do get snapped up.

Caen/Ouistreham to Portsmouth is overnight - although not a very relaxing one as it leaves France around 11:30pm and arrives in Portsmouth about 6:30am. If I get 5 hours sleep on it, I count myself lucky. Also be warned if you’re not booked yet, there may not be cabins available for Friday or Saturday sailings, ie they’re all booked.