OP, your ‘investment’ and just as importantly, tenants will be quite safe from those you speak of. Not least because this rural idyll is unaffordable to the local people and all the houses are also investments made by similarly affluent, hard working and driven members of our society, used as occasional weekend retreats and otherwise, empty.
Your playhouse lead roof is safe my friend, so long as the tenant occupiers remain vigilant and deem their own personal chattels valuable in one way or other.
Maybe, when you downsize and find a little spare time, you could offer to help within this project and further your understanding of those you have little experience and knowledge of?
😉