OP says "they should not have a say in how the tenant lives as long as they are not wrecking the house or causing a nuisance to neighbours and as long as the property is returned in the same state as it was let out (hence the deposit)."
Utter, utter, twaddle. The deposit - which I bet is under £1K - would not re-carpet the house, replace chewed kitchen units ( my brother's puppy did that), replace peed-on furniture , relandscape a knackered lawn, not to mention possible dog faeces left in the soil, etc etc.
Are you just plain dim, or plain selfish?
The landlord can do WHAT THE HELL THEY LIKE! It's their house, not yours. what an attitude, where you show so little respect for someone else's home.
It seems you are hell bent on breaking your tenancy- well, go ahead teach your kids how to be a responsible person, abide by the rules, and I hope you all get evicted.
You aren't worth wasting time on.