HERE IS A SENSIBLE ANSWER FOR YOU:
Presumably this is Oldbury B69?? And you didn't say where to in Cornwall BUT ........ Oldbury to Truro for example is 153 miles ..... and I should imagine you car does about 35 miles to the gallon (of you don't drive like a bat out of hell!!!) and there are 4.5 litres in a gallon - therefore you car does about 8 miles to the litre ..... so 153 miles divided by 8 means you need 19 litres of fuel, which means that at, say, �1.20 a litre it will cost you about �23 ........... in other words too bl**dy much!!!!!
EK