If you buy a used Sky+HD box from, say, Cash Converters it will likely come with a viewing card already in it for your area. If there is no card the box will by default show BBC London and ITV Central West Midlands. You can buy a Freesat-from-Sky viewing card from Sky for a once off £25. The card puts the regionalised programs in the right place, e.g. in Yorkshire BBC Look North will be on 101 and ITV Calendar will be on 103 etc.
You can (if it is still available) record the free-to-air channels by paying a monthly fee to Sky of £10. The control of recording or not is done over air.
If you go long periods between uses of the box you will probably find that some channels have disappeared. All you need to do is leave the box switched on and active and the missing channels will reappear within 48 hours.