I'm in the same boat as IanT and I think they are standard charges. With our trade-in and the price I was paying for diesel it worked out to be a no-brainer doing it this way compared to buying the whole thing... and I'll swap or trade it in at the end.
seems about right. The RCI finance contract for my PCP agreement states an excess mileage charge of 1 pence per mile. If I went 20k over my mileage allowance (which is looking increasingly likely as I've already done over 6k in 2 months) it'll cost my company 200 quid.