As has been commented, the UK converted to the metric system (sort of) over a twenty year period. Thus although the weather forecast is now in Celsius, they still mention the Farenheit temperature, and a lot of things (like Simon said about buying petrol by the liter and measuring economy in mpg) are 'mixed. I was lucky, going through school during the conversion so I know that there are 4.55 litres in a gallon (that's an Imperial Gallon, the US gallon is different), 1.61km in a mile, 2.2 pounds in a kilo, although Cesius to Farenhiet convertion is beyond mental arithmatic for me (Tf = ((9/5)*Tc)+32 or Tc = (5/9)*(Tf-32), I mean, come on) and I just know that 0=32/28=82/100=212
The Euro is something the UK has not adopted, and the way most people carry on it sounds as though adopting the Europe will have made the defeat of Napoleon and all intervening European history pointless: living in Holland as I do now, it's just silly, as any fool can tell you that the British pound will be dead well within fifty years.
The pound is an ordinary decimal currency, 100 pence in a pound. Pounds, shillings and 'old' pence were the pre-decimalisation currency which was used prior to 1970. In this there were 20 shillings to a pound, each shilling consisting of 12 'old' pence, thus 240 'old' pence to a pound. If you see an old film where they say things like "That'll be 3 and 6 guvner, stone the crows and mind your plates of meat on them pears, gawd bless us every one", they mean 3 shillings and 6 pence, or 42 'old' pence, which is 17.5 'new' pence.
There were coins like the Farthing (1/4 'old' pence), the Groat (4 'old' pence' (okay, that was phased out in the 19th C), the Florin (2 shillings), the Crown (5 shillings), and a unit of currency called the Guinea (21 shillings or 105 new pence), which for reasons I cannot be bothered looking up is used to this day when selling premium horses. The main reason for the decline of Britain from the late 60's onward is that having such a complicated currency exercised brains more, and with the advent of decimalisation there was a 'dumbing down'.
I think that tyres use an international system that is a weird blend of metric and imperial.
Southern Europe has temperatures in the 90's F every summer, and parts get even higher. However, the lower levels of relative humidity make it a lot more bareable than many parts of the South and East of the USA. In the past twenty years AirCo has gone from unusual to not uncommon in public places, but is still quite unusual in family homes. However, if you live in a house that is built in traditional styles, you don;t NEED AirCo; last week I went from 95 F+ heat into 65-70 F 'cool' by walking from outside into old houses with thick stone walls - this wouldn't work quite as well in a humid climate, but round the Med it's fine and dandy and is how people have lived for thousands of years without electricity bills.
Due to England considering 70 F to be a good summers day, and 80 F to be excellent, AirCo is very uncommon in English homes, although thankfully many modern public buildings have it now.