2011 Mk4 Mondeo MC 2L TDCi starting Issues

Sorry if I'm posting in the wrong place... there are so many posts that its confusing... Any help would be greatly appreciated :o)  I'm an English guy living in Sydney, Australia and would like some advice regarding the issues I have with my car please.  I have a 2011 Mondeo Mk4 MC TDCi Titanium Hatch - It has 83k kms (52k miles roughly) that's having issues on starting.

I go to start it in the morning - I push the start button and it will start and then cuts out.... i push the button again and sometimes it will start and cut out again, other times the revs will be slow and laboured for a few seconds then it will settle down and revs will be normal and the car will be fine to drive as normal.

When I come to the car in the afternoon/early evening after working for 8hrs, the same thing happens again.  I found that if I went to start the car at lunchtime (after 4-5hrs) it would not have issues starting 3-4 hrs later when I went to drive home.

I took it to my local garage and they had a look... they told me that they couldn't really do anything and that I should take it to a diesel specialist - all the guy could tell me was that there were no fault codes on the ecu and he thought it was losing fuel pressure so maybe an injector could be leaking - the problem was that the symptoms only show up once every 5+ hrs or so.

I spoke to a couple of different guys on the phone yesterday and described the issue... One said there's a cut out solenoid in the pump that can play up (?) and the other said about leaking injectors too - either way they would need my car for a few days to find and then fix the issue.

A friend in the uk with a mk3 mondeo tdci had similar issues and garages told him it was injectors- it seems to be a standard go-to answer to this kinda thing - it turned out to be crank/camshaft sensors. He told me to ensure that whoever I take it to does a 'leak back test'.

Can anyone give me any info on what it could be, what to look for, etc as I want to try to limit the $$$ that I'm inevitably going to pay out...  If its going to be expensive I will trade it in while its still running ok once its been started.

Thanks in advance