Ive been looking on various car forums and it would appear several others have the same idea to go at the same time as us.
This is probably due to the amount of time the ring is open..
So I would suggest your book Eurotunnel to be assured we all get on the same train.
Do not forget to book when going through the vehicle details section, "to say you are carrying bikes on the roof"
(Before you used to have the option of booking over 1.85m)
The price has also started to creep up it is now £136