To give a bit of an update, I've taken it to Ford today. Had a call saying no noises found and I can come collect.
I went to Ford and asked to speak with the technician. They said he'd be 10-15 mins so I said perfect, I'll go get it warmed up now and show him the noise. I got it warm, did a medium pull or two after temps up and as expected... got back to Ford and left idling while I listen - noise is there.
The technician came out and listened carefully for a few minutes and suspects it's the dual mass flywheel, early signs of defect. Waiting for them to contact me with another diagnostics appointment now...
Going to get my warranty involved at this point and pray I don't have to pay too much ontop of my basic warranty allowence. Of course they may as well replace the clutch and all that at this point.
Might explain some gearbox knocks I intermittently experience too.
This is all at 43k which is a shame but this is the risk you take with used cars!
The plot thickens....
I went back to my local Ford today as they'd yet to contact me and I want to move fast as this clearly dragging on.
They gave me another diagnostic date of 24th... with a £600 ($832) bill, solely based on that fiasco yesterday.. where the one young tech who listened to the noise for 5 minutes and suggested Flywheel... they wanted to take apart my car to check the flywheel. No talk of checking anything else, literally a sticky label saying £600 on a report document the receptionist was holding.
Obviously at this point Im flapping with Warranty and I started contacting the independent car dealer I got the car from last month.
The independent dealer suggested I get a second opinion and that ford official garages are rip offs... in fairness they might be right because I took it to a general motor garage (Halfords autocenter) who FOR NO CHARGE literally minutes after a random phone call to them asking for help, drove the car with me... acknowledged the noise got it up on the jack and we all inspected it together.... for NO CHARGE and we're back to the noise 100% originating from the fuel tank. If you put your hand on the tank it's apparent... also the plastic tank rests on some metal braces under which look like they've been mishapen ever so slightly (the plastic tanks clearly deforming with THE EVAP ISSUE)... I do see the humor and wish I didn't doubt myself but more than that... I wish I never dealt with Ford in the first place. I was under the impression it was 'the right thing to do' for keeping car value and wanted to believe they'd give me a better service than independent garages. This is clearly not the case and I'll do all my services through Halfords and never step foot in a dealership again.
So now it's booked in for £90 diagnostics at a Ford specialist referred to me by Halfords (who charged me nothing, I like to keep saying lol) and the dealer I purchased the car from is being responsive and involved. Under law they have to make it right as the problem was with the car when I purchased so... we will see light at the end of the tunnel soon guys.
This is post is becoming my car diary but maybe, just maybe a person in same boat will read this one day and itll be useful.