Resolved! Jerky at slow speed

Can you see it in my attachments?

now we can

I can't find this thing

I fear you may be looking at the wrong side of the engine. Your pictures are of the right hand side of the rear of the engine, you need to look at the left hand side of the front.
Sort of above the clutch slave cylinder.

Photo please

Nope!
It's on the exhaust manifold side of the engine. Looking from the back of the car, the sensor is far left of the engine on the coolant outlet.

Arrow points to sensor

Never one to turn down a photo opportunity however on this occasion I’ll decline. Not wishing to remove the hard top, unclip the rear of the hood & raise it, remove carpet & sound deadening, unbolt the cover plate in order to take a picture of the sensor’s whereabouts.
David’s picture & my description should have alerted you to its general geographic position & as I now see his second picture has reenforced its whereabouts.

Can only see a black one, is that it?

Yes, that is the engine coolant temp. sensor for the ecu.
If you are replacing it ensure you get the correct one, (MEK000030 followed by a letter depending on whether you get oem or aftermarket) NOT the sensor for the coolant temp gauge.(YCB100370 or YCB100420))

The brown sensor mentioned was used on mk1 Fs, later vehicles used a black sensor.

I was going to get this one

https://autobarn.com.au/ab/Autobarn-Category/Shop-our-Full-Ranges-by-Brand-%7C-Autobarn/Tridon/Coolant-Temperature-ECU-Sensor/p/SP115102

which is the same as this Ebay one

Tridon Coolant Temperature Sensor for MG MGF TF 1.8L VVC 18K4K DOHC 16V Buy It Now

Might I make an observation. We have got to start somewhere on the knowledge ladder with our cars, however it is not the function of the T-Bar to diagnose your problems or advise which part to buy. You have the information on your car & David has furnished you with all the information to make an informed purchase; to ascertain which sensor you need, remove the connector & observe the cap colour & you'll be well on the way to deciding which to buy.
It is also polite to thank each contributor for the help received.

My my you are a happy sort, I didn’t give you incorrect information & my comments are as valid as any other contributor. If the general consensus of members on here is for me to butt out I will gladly, however until that happens I will feel free to comment as I feel fit.
Writing in upper case, with aggression & with very little provocation might give other members an indication of your personality & they, like me, might be disinclined to give you any assistants & a wide berth.
I wish you well with your problem & hope you resolve it to your satisfaction, I will however be striding over any post with your name attached.