TMB

You wouldn't see enough of the valves through the ports with the camera I reckon. Check on your spare head?

Welcome along 🙂 17x2.5mm is the correct size. It is Skoda part number N90422201. Same for all years of 1.4 MPI, 8 valve. https://skoda.7zap.com/en/cz/fabia/fab/2003-225/9/906-906000/

I know you've checked the servo hose but they can crack at the bottom out of sight. Worth having a really close look.

It does seem odd, Pete.

Ah, here we are (150 Nm + torque a further 1/2 turn (180°) ..... https://workshop-manuals.com/skoda/fabia-mk1/power_unit/1.4/55;_59;_74_kw_mpi_engine/enginecrankshaft_group_pistons/disassembling_and_assembling_engine/procedure_for_tightening_the_screw_for_crankshaft_belt_pulley/

The Haynes manual says 90Nm and 90 degrees. Doesn't seem to mention different bolt heads though.

At least it was cheap 😁

No problem 🙂

Has it been scanned for fault codes?

Yeah, and engine size and petrol or diesel 🙂