Which size door to use

[littlecookie]

I've fitted a good few internal doors over the years but my sons house has a casing that measures 800mm by 1970mm so it's too wide for a standard door but too narrow for a 2ft 9" door as I know your limited to how much you can cut down by ,all the doors in the house are smooth finished so ideally he needs one similar struggling to find a solution
,thanks

 

[foxhole]

Reduce door liner width to suit small door width.?

 

[littlecookie]

Reduce door liner width to suit small door width.?

Like build it out with some smooth timber battens ?

 

[foxhole]

Remove architrave , line with more timber of same width then refit wider architrave to hide join.

 

[Cookie74]

Either solid door cut down to size or build out casing like foxhole said

 

[cjard]

Pics?
You might be able to order planed-all-round timber in the same species as the door and extend the door. If the door is painted it's even more likely to go unnoticed. My doors weren't tall enough, so each door has been extended by 30mm top and bottom. People only notice when it's pointed out, unless they're a pro trade. I could make an even tighter job of hiding it by routering a groove along the join, and making a feature of it, but I've got a lot more to do at the moment