Essential tool kit? (Length of piece of string...)

We're hoping to head off for a trial weekend very soon with our caravan. I'm wondering what an essential tool kit / spares kit needs to have. Bearing in mind I'm not a whizz repairer of everything in sight, and accepting that the length of a piece of string is different for everyone, I'll be grateful to learn what stuff you regard as truly necessary, or wish you'd had with you when you didn't!

I'm not including domestic equipment in this, like kettle, or loo stuff, nor things like the corner steady winder, and I've already bought my gas bottle spanner,  but spares and running repairs items. It's a fairly low tech caravan, no central heating nor shower, & we choose no TV, (though it does have water heater, cooker, fridge, motor mover), so we won't need the more esoteric items mending.

What would be on your list, please?

Thanks!

RIchard