Mark3 Mondeo 2.2 TCDI Titanium X Diesel (2009)

Bought it the other day and it’s been running like a dream, no problems.

Today when I went to start it (no-key push button start) instead of it firing up within a second or so it took about 3 or 4 seconds of turning over before starting up. Once it was on it was fine, no problems. 
 

I drove the 35 miles home, everything was fine except when I approached a roundabout the engine just cut out. Not sure which gear I was in or what speed I was going but it wasn’t juddering the way a car would if you were going too slow for the gear. It took a second or two but I started it back up and got home no problems. 

It has never misfired etc, in fact this is the only things that’s gone wrong. It has 180,000 miles but it very clean and looks like it’s been well looked after. I plugged an OBD in but it showed no faults. 
 

I don’t have time to get to a garage for another 10-14 days so I’m hoping I can get some ideas of what could be causing this before I go. I’m not very tech minded so I’m not sure what I’d be looking for under the bonnet. 

It hasn’t happened before, so does anyone have any ideas of what it could be?

Mine's a different engine (though still a diesel)  but mine also turns over for a few seconds before starting when it's cold (i.e. when I see the glow plug symbol).

Sudden or intermittent engine cut-out can sometimes be a camshaft or crankshaft position sensor, but I think you'll want to run diagnostic check on it to know if there's any problem.

2009? It'll be a mk4. 

OBD readers of the generic type can only read generic errors. If you want to read Ford-specific errors then you need a Ford-specific reader. An investment would be to buy one from  Tunnelrat Electronics, either one that connects via a USB cable to a Windows laptop, or a version that connects via Bluetooth to an Android device. You will also need to download Forscan software (free for Windows) or a small fee for Android. Then you'll be set up for Mondeo life! 

Other slightly more expensive solutions exist, maybe someone else can advise...