How much liquid can I take in hand luggage with Jet2 can I have 2 bottles of 100ml or only 1?

You can take more than one, however all liquid containers must hold 100ml or less (100ml of liquid in a larger bottle is not permitted.) and must be placed in a clear plastic sealed bag (zip-loc), the bag should be 20cm x 20cm or smaller and you are responsible for providing it (not least because they sometimes charge an unbelievable price for them at the airport).