As a piano, it may be fine. Disklavier technology has evolved significantly in the accuracy of playback and recording. The solenoids and sensors (if recording is featured) do require servicing and maintenance as with all things mechanical - and worn / noisy parts need replacing. The environment the piano has been kept and the amount the Disklavier has been used does effect the performance, reliability and longevity.
So, the issue with an imported model (one that has been built for Asian climate, used in Asia for 15+yrs and then imported to the UK) is that this information cannot be verified other than thorough inspection of the components. A humid climate does wear a piano more... this is clear from examples we have had of the same vintage - one being ex-Japan, one ex-UK.
If all is checked by an independent technician (not affiliated with the supplier) and this includes the Disklavier components and the price is significantly less than new, then great. Have some guarantee in place in the event of the piano drying out in a heated UK home. The effects can be: tuning instability, dull tone with short sustain, loose feel to keys and action parts, worse (but unlikely) buzz from split bridge/soundboard. As these symptoms can occur months after being in your home - what would happen? Think of it as buying something privately, you are taking some risk but then you are paying less also.
With your assurances in place... if you have played the piano and you really like it - go for it.
I respect the fact that
a new Yamaha Disklavier is a far better piano in every respect, but it also costs more.
Topic: 'Gray' Disklavier