As below The bobbin case has come out of its drop in housing and the manual is not very helpful. Tried to get it back but it will not seat properly. Are there any simple ways of doing this?

Good that you included the photo...
The 2 pieces look like the hook and the retainer ring that hold the bobbin.
The piece to the left is the hook ... one to right the retainer ring. The bobbin fits into the hook.
There is a diagram below that should help.
The two black 3/4" long levers need to be twisted outward...then put the hook in ... followed by the retainer ring .... and then twist the two levers back.
Generally the two parts will only fit in a certian way to be able to successfully twist the levers back ... could be some trail and error
I tried posting another diagram but fixya would not upload it ... I will post this answer and then try to add the second diagram

the bobbin casing is not clipped in place properly, lift the lever and push in place then lower the release lever.
or try another bobbin casing, these are only 30p on Aliexpress with free shipping.

Usually you need to hold the little latch open until the bobbin case is seated in the machine. Perhaps this video will help;

Singer Promise 1408 Get started

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The owner's manual should have instructions.

Also search for some videos on YouTube:

Bobbin case seating 2

Inserting Bobbin Top Drop In

Fixing Top Load Bobbin

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after removing the needleplate and gray bobbincase retainer, manually rotate the handlwheel so that the tip of the hook is between 11oclock and 10oclock. carefully insert the bobbincase into the hook assembly so that the gap in the bobbincase is centered below the feeddogs. manually rotate the handwheel slowly to confirm that the bobbincase is fully seated into the hook assembly. reinstall the gray retainer and then the needleplate. again manually rotate the handwheel to confirm that everything is seated correctly.

I suspect the "housing" you refer to is not seated completely. Be sure to wiggle it until it slips into place. Once it is seated, the bobbin case should seat firmly as well.

Is it the bobbin or the bobbin case that is banging around? If I don't seat my bobbin case properly, it rattles and eventually falls out. Your bobbin case may be damaged, in which case, the bobbin is not going to fit properly. I dropped and stepped on my bobbin case once and the machine had the same symptoms. Then there's the obvious answer, a wrong size bobbin got mixed up with your bobbins. I've had that happen when I've taken a class with others. We all share tools and sometimes the right ones don't get back to their proper owner.

You may not have the bobbin case seated properly in the bobbin well. Make sure the flat edges go underneath the metal flanges that are there to hold it in. I'm attaching photos of a similar problem I answered earlier that might help you understand how it goes in.

Below are the directions I sent with the photos...I hope this helps you! Good luck!

"This type of case can be a pain. First in photo 1, on the silver flange marked in a red circle there is a rectangular hole marked with a green circle. using a flat head screwdriver, insert into the rectangle and turn to the right. This should move the flange tongue marked with a blue circle towards the back white wall of the bobbing well. In Photo 2 take the black bobbin case and place in the bobbin well area marked with the pink spiral. Tilt the case slightly to insert the flat tongue marked with an orange X on the black bobbin case under the flange marked with an orange X in the bobbin well. Now let the black bobbin case sit in the bobbin well marked with the pink spiral. Now in Photo 3, you want to turn the black bobbin case to the right so the flat tongue marked with the orange X will go underneath the flange marked with an orange X. The other flat area marked with a purple X on the black bobbin case should line up with the purple X in the bobbin well. Once the black bobbin case is seated in, repeat the steps from Photo 1 in reverse to get the silver flange back over the bobbin case to hold it in place. I hope you can understand my directions and I hope this helps! Good Luck!"

The bobbin tension sounds too loose. This will help if you have a bobbin case and not a drop in bobbin. Let me know if you have a drop in bobbin:
Setting bobbin case tension:
Put wound bobbin in bobbin case. Thread it in case. Hold the thread and carefully let go of the case only holding bobbin thread. The case should NOT move. Quickly let your hand drop 2-3 inches to let the bobbin case free fall for 2-3 inches, the bobbin case should move slightly then stop. It moves because it let’s a little thread off the bobbin. It should then stop .5"- 2" of thread should release. If so, your bobbin case tension is right. If it’s right then begin to look at your top thread tension. Always Always start with a properly adjusted bobbin case, then adjust your top tension accordingly.

Same problem. No help at all from manuel. Just glad to hear others are familiar with problem. Thought it was just me!