Hi
Could someone tell me, if I disconnect a rear height sensor, to clean and lubricate, do I need an iid tool to reset, or will it be ok to just plug in again?

It will be ok to remove and refit.

Not sure I understand what you hope to achieve by removing and 'attempting' to clean. They are sealed units that are non serviceable. New ones are not expensive but do require to be set up when fitted

I just really wanted to clean the electrical.connection.
It seems.to.be sitting a bit low on one side, air bag seems ok, does not drop overnight ect
Thought it would be worth a try

You could try some spray cleaner in the plug and socket