Hi, If you are flying with BA they can keep the bags overnight at heathrow if your connecting flight is the next day ( up to 24hrs connection time ).Needs to be on one ticket. I have not heard of any problems with this and have been offered this on all my flghts with an overnight but I generally get the check in staff just to tag it to Heathrow as i like to have my full range of toiletries etc and I can put my gym/swim kit in the checked bags the next morning. If doing this then you will need to have your overnight stuff and clothes for travelling to MCO in yout had luggage and also any overnight toiletries will need to fit into the hand baggage plastic bags ( no liquids above 100ml in hand baggage)