Hello from Kendal on the edge of the Lake District. I ran past Grizedale only last Monday as it happens. Lovely sunny day and looked to be as busy as ever there.
In addition to the YHAs already mentioned, you might like to look at Dalefield in Ambleside. It’s a lovely self-catering property that can sleep up to 10. The owners actually live there (ask for Paul and say ‘Paul Johnson’ sent you!) but vacate the property whenever it is let, I believe. Alternatively, I think you can stay on a B&B basis. It would be a good base and I pretty sure they could accommodate bikes too.
Another possibility is the Queens Hotel in Ambleside. I’m not sure what bike storage facilities they offer, but I’m sure they must have something as it’s a fair sized hotel right in the middle of the town.
And if you ever re-visit the county as a smaller party of 4 or less, do please look up my own holiday let ( a self-catering apartment in Kendal ). Cyclists are very welcome – you can leave your bikes secured to your vehicle in our secure, keycard-accessed car park at the base of the apartment building – or, if you wanted added security, there’s a cycle shop just a short walk from the accommodation (Askew Cycles) that will store bikes for you for a modest weekly fee.
Enjoy your visit,
Paul