For this you need remote start module/alarm, immobiliser bypass module(key kept in box) hidden away in car. Last but not least yo . Need a Canbus converter which gives correct wires for remote start and immobiliser bypass
Is this an OEM set up you're describing?
Aftermarket alarms with engine start are relatively cheap, way cheaper £100. Albeit not a "brand"
Yes it's an insurance risk as even the likes of Clifford versions which have remote engine start are not thatcham approved.
Also security wise, as said the car cannot be moved without a key but I guess from an insurance perspective opportunists wouldn't stop to workout whether they can actually drive the car away or not...