Approved locks may be a requirement. In particular in London and other urban areas. High contents sums insured may also trigger the approved locks condition.
Wooden doors, 5 lever mortice deadlock to British Standard BS3621. Also known as a Chubb lock. There should be a kite mark on the lock plate confirming BS3621.
UPVC and aluminium doors, with a multi point locking system. When the handle is pulled up to lock with a key, bolts and hooks shoot into the door frame.
Window locks, operated by a designated key. On all accessible (reached without the use of a ladder) windows.