Carpentry question re: doors

[dirty boy]

I want to order some doors and liners, but am unsure as to what exactly I should be ordering.

My opening is as follows (height is standard and gap at top will need to be filled)



The door I want comes in the following sizes
H1981mm x W610mm
H1981mm x W686mm
H1981mm x W762mm
H1981mm x W838mm

I'm assuming the 838mm one won't allow enough room for a liner, so if I go for the 762mm one, i'll have 78mm for liner/casing/frame? (not sure on the technical term)

So if you were a carpenter, what would you be ordering along with which door to fit to the opening?

Thanks in advance.



Picture of door I'm after is below if that helps?

[Spudler]

Yes go with the 762 and pick up a lining from your builders murchant, that will leave you with about 14mm overall for packing.
If using expanding foam after fixing cut some battens or off cuts and place them in the frame to stop any bowing.

[Simpo Two]

Also, that door looks like quite an easy one to cut down, so you could go for the bigger door and trim it down to exactly what you want.