Can someone confirm the ruling regarding bringing my dog back into the UK, we are going to france via the channel tunnel on a sunday and coming back on a thursday. If we got the train (from folkestone) at 14.00 and the train back from Calais at 13.00, would it be possible to get my vet in the UK administer the tapeworm tablets and sign the passport, if this is possible what time is the earliest on the sunday this could be done?
I am ready to book the train but need to get my timings right.
Thanks.

If your traveling home on a thursday at approx 1 pm you could get worm treatment done in late
afternoon on the previous Saturday or anytime previous Sunday. You need between 1 and 5 days prior to check in to travel and need to check in a minimum  of about 45 mins prior to your train leaving. Once checked in you are classed as back in UK so times ned to work on check in time not arrival time back to UK.

I meant to say 'what is the LATEST time on the sunday the tapeworm treatment could be done? (I am 2 hours from Folkstone).

Any time on Sunday will be acceptable if you plan to travel back on the following Thursday as over minimum of 1 day and under maximum 5 days limit

Also is it compulsory for the dog to be in his cage throughout the journey (from check-in at Folkstone to arriving in calais) or can he be loose?

The dog will need to remaining the car whilst on the train not a long time approx 35 mins. Whilst waiting  to load you can get the dog out and walk it around