Hello, I hope the following assists you.
As the glow plug light is flashing the engine management has detected a concern with a sensor or actuator, this will obviously be the cause of the non start condition.
By far the most common faults to stop this engine starting are either a camshaft or crankshaft sensor or a faulty injector causing no fuel pressure.
If the camshaft sensor body is black then this is very likely to cause the fault, it will need replacing with a grey coloured sensor, the camshaft sensor is used by the engine management for injection purposes, if the signal is missing then the engine management will set the fuel to zero to prevent engine damage. The same applies for the crank sensor, if the signal from this is missing the engine management will set fuel to zero.
A faulty injector will cause low fuel pressure, the fuel pressure is measured by the engine management, if the target pressure at cranking isn't reached the engine won't start.
Unfortunately the only 100% certain way to confirm the cause is to retrieve the fault codes from the engine management such as P0340 would indicate a camshaft sensor concern,the above are the common concerns on this engine.
If you want to do this on a DIY basis then you can obtain a diagnostic tool from Ebay for around £40, this is cheaper than having a garage check for codes but if you want a garage to do it nearly all garages are equipped to retrieve EOBD engine codes now.
Start with these points, let me know if I can advise further and I'll reply as soon as I'm able to.