On the top of my head
Apart from the usual checks to do on a car, here are the common Accord diesel issues.
Even if you experience these, they are well covered on this forum so you will have no trouble getting them sorted.
-Check for exhaust fumes from the manifold (these are known to crack) although considering the mileage may have ready been replaced by now.
(fumes will go into the cabin) this was a honda TSB
-Another TSB - Alternator belt routing was adjusted for a different route as the older route was too tight and killed alternator bearings.
Symptoms of a dying alternator bearings - Clicking sounds coming from the alternator when engine is running
-Drive axles can cause vibration upon acceleration. People who drive these cars hard or remap them can kill the axles quickly.
(common issue)
-Check top power steering hose and lower power steering cooler pipe on lower grill in front of rad. I replaced both of them in mine now.
Due to the age. Front cooler pipe perished and top high pressure hose pipe leaked. Common issue as the vibration where its anchored will penetrate the hose over time.
-Check to see if the nav disc is present and not a copy although the nav system is old its always good to check if its working.
-Bluetooth module (as mentioned) another common issue. The module dies and just drains the main battery. You probably wont be able to check it anyways but worth a mention.
Plenty of threads on the Bluetooth issue - I've just installed a parrot system on mine
-Often over looked. The fuel filter. These need to be changed every 25k miles. Check to see when it was last done.
-When car is at operating temp. Turn the car off and then restart it. If it fails to restart then its the pressure relief valve that needs replacing
Also clutches are expensive on these cars. Around £1200 supply and fit. So it can write the car off getting it done.
Check the condition of the clutch.
The 7th gen accord does not have a DPF only an EGR but this can be cleaned quite easily as its positioned on the front of the engine.
The key with high mileage cars would be its service history and service intervals between oil changes.
Hope it helps
I have had mine for over 6 years now and learnt soo much about them.
Despite its common issues, service them every 6k miles and use decent fuel. They are very reliable cars.