Thanks for the replies guys, I appreciate that.
I bought the car a couple of days ago, but looking at your prices, I am a little concerned I might have overpaid on it!
It's from a Lexus dealer and after doing plenty of research for prices on autotrader and the Lexus website, the price appeared in-line.
For reference, I've paid £19,000 for a 55 reg 45k mileage SE-L model (Emma wanted some of the features on the L model). I appreciate that I can buy it slightly cheaper privately (or non-franchise dealer), but I didn't want to take the risk on it (and also have the official Lexus warranty).
The dealer also mentioned the service option paid for with direct debit, so I will definitely do that - sounds an excellent idea.