Kingsand/Cawsand and Plymouth: wet weather ideas?

[MogTheForgetfulCat]

Hello, we are off to stay in Cawsand for a week from Friday. Desperately hoping for good weather, and have 2 DSs (3.5 and 1.5) who are generally troopers about going to the beach in iffy weather. But would like some ideas about what to do if it absolutely chucks it down.

Have heard that we can easily take a ferry across to Plymouth, so thought there might be some good indoor stuff there. I used to live in Plymouth (and seem to recall it had a good aquarium?) but that was a long time ago...

Will be wathcing this with interest. We're going to the same spot a week later with dcs of the same age as yours.

Aquarium is on our list of things to do. I think there's a ferry over there at 10.30 (there are 4 a day). Also Eden Project if it rains (we've been twice in the past year so won't bother if it is fine).