Hydraulic tappets

Looking at your excellent video ,why does the inlet manifold have to be removed it isnt attached to the cam casting Len

I agree with what you are saying/questioning about inlet manifold. I can't see that it needs to be removed to do the tappets. So just carry on with the job, after all you don't need to remove the head to do the tappets.

When removing the camshaft casting ,are the bolts that hold it down ,the same ones that secure the head down as well .If so it means the head is loosened when removing the cam holder !!! Len

They shouldn't be Len!!

Seperate bolts..quite low torque settings on Toyota...12ftlbs...check your manual Len..

Hoping it doesn't come to that.
If you have to remove cams...take out the two bolts securing the cam wheels to the camshaft. Mark the wheels against the block with paint.  Clamp the timing belt to both wheels...small vice grips etc. the cams will pull out from the wheels. There should be a dowel on the end of the cams so keeping the belt tight on the left slip the dowels in to the wheels when done. Check your marks..saves removing the belt and the timing cover housing.
Changed cams many times that way..some times 2-3 times in a day.
Hopefully flushing oil does the trick!

Just checked my VVC head to make sure, so the answer is no the head bolts do not need to be removed unless you are removing the head. So good luck as you continue, good advice from TA22GT also.