There are still restrictions on what can and cannot be carried in your hand bagage and these restrictions aren't only from UK airports. Just about every airport in the world seems to restrict the amount of liquids you can carry, with some even banning liquids and gels completely!
Nobody can tell you your baggage allowance though as Opodo is not an airline, but a travel booking website. If they are flying with a scheduled airline, possibly British Airways or Cyprus Airways, they can expect 20kg checked baggage for economy. Hand baggage is usually 5-6kg, although I have flown with some airlines lately that have allowed up to 12kg in the cabin!