Some conflict here in the Roisin household.
I come from a family where you bring everything in case of emergency. My dad would always have a bivvy bag, extra clothes, full waterproofs, whistle, complete first aid kit, etc.
Dh insists if you check the weather forecast carefully you actually need to take very little with you.
So for a day walking in the lakes, say 5-6 hours - including climbing to considerable heights, and in a quieter/off the tourist track area. What would you take in your bags as a minimum? (Boys are 9 and 10, so are used to carrying their own packs.)