Restrictions on carry on luggage seem only a little daft.
Aerosols? No way guv, we've all seen Live And Let Die.
Mouthwash? Yaw kidding, you might be Arthur Brown.
Drinks? Right out. Remember Carry On Spying (the same joke also appeared in The Living Daylights, in case you're not yet of A Certain Age)?
However, those lucky retailers who have airside outlets (you may call them shops) are literally quids in on this one. Your friendly WHS will hit you for well over a quid for any liquid refreshment; Boots' are rather less mercenary.
Some airports across mainland Europe have drinking water fountains airside, so you could take an empty container through security and then fill it for free. Proud Brits will be relieved to know that a quick check at Liverpool, Manchester and Birmingham airports reveals that nothing of the sort is allowed to hurt those all-important revenue streams.