A Finance Lease is method of repayment, where the monthly rental is determined by how much the car costs, how long the lease runs for, and how much (estimated) the car will be worth in the future based on the proposed annual mileage
Fixed rate means a loan on which monthly repayments are fixed. They will not fluctuate in line with normal interest rates
Flat rate is the monthly interest rate. Finance providers may quote the flat rate instead of the APR because it sounds cheaper
Forecourt finance may be offered by car dealers as and when you purchase a car. However, the rates offered are rarely the best on the whole market, and it is always worth shopping around for car finance to find the best deal