5 lever mortice deadlock for very thick timber door

[toomuchworknotenoughtime]

I'm in the process of having a solid oak door made but because of the design it needs to be 56mm thick. Great. Nice and secure. But ....

All the best BS3621 5 lever mortice deadlocks seem to specify a maximum door thickness of 54mm. Ideally I wanted some sort of key restricted access and hoped a Chubb/Union deadlock would meet the bill but I can't find one that will fit a door more than 54mm thick. I don't particularly want to end up with a bumpable or pickable cylinder deadbolt. Does anyone have any suggestions?

 

[speed]

go to a locksmiths and get a long key cut,
this is the first link that came off google

http://www.lockshop-warehouse.co.uk/acatalog/extra-long-key-union-5-lever-locks.html

 

[DC77]

It is known as a rim length key. Suitable for the Chubb/Union 3G114 type mortice locks.
DC