Replace mortice deadlock in wooden door

[fraccalo]

Hi folks!

My flat's wooden door has an old mortice deadlock that needs replacement.

It's one of the old Chubb locks, that apparently (from the info I found online) is now rebranded Union.
However, I can only find a few locks online that have similar size (but not 100% identical-which worries me a bit) but are 4-5 times the price of "more modern" models, which seem much more low-profile than the old ones, .
These are the pictures and measurements of my old lock:
https://ibb.co/TLbCzfs
https://ibb.co/fMbK0Nm
https://ibb.co/5LS8mpT
And this is a possible replacement:
https://www.lockshop-warehouse.co.uk/ac ... dlock.html
which however costs much more than other models (which can be found at 20-30 quids), and measurement-wise is slightly taller than my current lock.

Do you have any suggestions on what would be the "best" thing to do, in your opinion?
I'd like to keep the current key hole and don't drill any more holes in the door, but I wouldn't mind to do some chiselling to make room for the slightly larger mortice lock, or use some wood filler and replace the old lock with a smaller one (however, I don't know how easy it would be then to fix the mortice lock on the wood filler with screws.. I suspect it might get a bit messy).
I'm really puzzled and not sure of how to proceed, any suggestion is very welcome :)

[Mike]

It looks a good replacement to me :)

[markc]

That should fit but does seem rather expensive.

I love the note regarding wanting keyed alike but not working with one key ?