i do similar miles to you mainly on road and i have a 200tdi and this is what i do at what times, bear in mind that mine leads a very charmed life and is garaged.
Also a good habit to get into is fixing advisories on your MOT as soon as you can after the MOT
weekly:
tyre pressures
monthly, all of the above plus:
fluid levels (all) and top up as necessary
bulbs and light function, and horn
6monthly, all of the above plus:
grease all grease nipples and props
underbody inspection looking for rust, damaged rubber gaiters, exhaust condition, new leaks etc.
check fan belt/pas belt tension
check handbrake and footbrake operation (adjust handbrake if necessary)
yearly, all of the above plus:
check fan belt/pas belt tension
change all engine, gearbox, xfer box and diff oils
change air filter, oil filter, fuel filter
drain sediment bowl of water (mine is ex-mil so yours may not have this)
check wheel bearings for play - service.change as necessary
check steering and suspension bushings for play - change as necessary
grease door straps, locks, hinges etc.
every 2 years, all of the above plus:
new fan and pas belts
change brake fluid
swivel grease top up
set tappets (should be yearly really)
rotate front tyres onto rear and rear onto front
other things are then time or mileage dependant, timing belt for example i would do 5 yearly. I dont do all those things on a religious 'one day' basis but more on a rolling basis, some years i might forget something and other years i might do something twice, plus running repairs etc.
more info here
https://haynes.com/en-gb/tips-tutor...ne-maintenance-guide-diesel-engines-1983-2007