If you are sure the previous services have been done correctly then you should be due a 10K service, which is just oil and filter.
The timing belt interval is 120K miles or four years, so check to see if it's been done.
Hydraulic fluid should be changed every two years.
I put this summary of the service schedule together a while ago from various sources.
Oil change service every 10K
- change oil and filter
- check brake pads and disks
Full service every 20K or 12 months, whichever comes first
- change pollen filter
+ check lights, tyres, wipers, "fan belt", toothed belt, steering, driveshaft gaiters
+ levels in gearbox, coolant, hydraulic fluid, power steering, 4wd, screenwasher
Vehicle exterior
- Door retaining straps: grease and lubricate locking pins
- Sun roof: clean and lubricate guides
Not in service schedule but worth doing - lubricate bonnet lock.
Additional items
every 40K,
- change spark plugs (petrol engines)
- change air filter
- change fuel filter (diesel engines)
Not in schedule but worth considering: change HT leads (if you have them)
every 40K or two years
4WD cars, Haldex clutch
- change oil and filter
every 2 years
- change hydraulic fluid
Gearbox oil: VAG gearboxes are "filled for life", a self-fulfilling prophecy if ever I heard one. There is no stated service interval. I've changed mine at around 100K before now.
every 60K or 4 years
- change toothed belt (diesel engines)
every 120K or 4 years
- change toothed belt (petrol engines) (This may have been revised down recently)
When changing the toothed belt consider changing the water pump as well. The pump is driven by the toothed belt and nearly all the cost of changing the water pump on its own is labour to get the toothed belt off and back on without disturbing the timing.
I've added the info below from David Hawthorne at Sere Motors:
Timing belt intervals PETROL
TIMING BELT RECOMMENDATIONS
LEON Mk1 / TOLEDO Mk2 AJQ, AGN, APP up to and inc vin 1MZYB - 180,000km, 120k miles
LEON Mk1 / TOLEDO Mk2 AJQ, AGN, APP, APG, AUQ, ARY, AMK, BAM vin 1MZ1R to 1MZ5R - 180,000km, 120k miles
LEON Mk1 / TOLEDO Mk2 1.4, 1.6 MPI all - 90,000km 60k miles (recheck every 30km, 20k miles)
IBIZA Mk4 BBU, BJX, BKV, BLZ all - 180,000km, 120k miles
IBIZA Mk4 ALL EXCEPT BBU, BJX, BKV, BLZ all - 90,000km 60k miles (recheck every 30km, 20k miles)
ALHAMBRA ADY, ATM all - 90,000km 60k miles (recheck every 30km, 20k miles)
ALHAMBRA Mk2 ALL EXCEPT ADY, ATM all - 180,000km, 120k miles
LEON Mk2, TOLEDO Mk3, ALTEA 2.0 FSI, TFSI all - 180,000km, 120k miles
LEON Mk2, TOLEDO Mk3, ALTEA ALL EXCEPT 2.0 FSI, TFSI all - 90,000km 60k miles (recheck every 30km, 20k miles)
IBIZA Mk5 all - 90,000km 60k miles (recheck every 30km, 20k miles)
EXEO 1.6 MPI all - 180,000km (check at 90,000km then every 30,000km)
EXEO ALL EXCEPT 1.6 MPI all - 180,000km, 120k miles
IMPORTANT NOTES
1) Timing belts need replaced every 4 years even if the mileage has not been reached
2) These are guidelines only
3) I have compiled this list myself based on SEAT's guidelines - it is as accurate as possible but human error can and does occur
4) SEAT dont always recommend the tensioner is replaced but we feel it is best practice to fit timing belt kits rather than just belts on their own