The first looks to be a Constantine Roman coin - nice piece of history, but not scarce. Probably worht no more than a £ or two in that condition.
Second I have not looked up, but smacks of Spanish to me. Probably silver and the most interesting of what you have.
Third is a George III - probably Halfpenny with date obliterated but likely 1806 or 1807. Not worth anythin much in that condition.
Fourth is a Victorian medallion...
Bulk lots - I can't see anything startling with a quick glance.
Best bet might be to find a local coin dealer who will be able to go over those quickly and tell you if there is anything worthwhile. Whereabouts in the UK are you? I am in the SW and would be happy to do it if you are in this area.