Yes, I would ask about servicing if I were you. I'm not sure about oil, but gas is once a year and electric once every 5 years.
Ask your landlord when it was last serviced, or it might say on the aga website. Does your tenancy agreement say who is responsible for doing it - there probably won't be any change out of £100 for doing it from aga. Are there any aga reconditioning people near you who could service it - as long as they use aga parts?
There are loads of aga books now, but a few years ago I bought 2 GH ones, but was a bit put out when I found the same recipe in both. However, I think the Caroline Blakeley one is the best, especially for the tips.
Folded washing on the simmering plate lid will 'iron' itself. If you sew, apperently the simmering plate is the ideal thing for sealing regilon plastic boning for bodices. The boiling plate is brill for darkening/scorching paper for treasure maps.
In England we had one of those airers that you pull up to the ceiling on pulleys. Sadly, where we are now, the kitchen has a false ceiling so we can't.
Their only downside is that they don't do grilling very well and deep-frying is dangerous. The only thing you have to remember is to use the plates as little as possible to avoid using too much oil. The crackling on roast pork is out of this world.
For Sunday lunch we used to buy a pork hock from tesco. Bring it to the boil in cider on the boiling plate with a couple of peppercorns and a bay leaf. Bang in the simmering oven overnight. The next morning take it out of the casserole and put on the rack in the roasting tin. Strain the juice - if you put a couple of sheets of kitchen paper in a sieve and then run it under the cold tap, the damp paper will let the juice pass, but hold back the fat. You can then reduce the liquid to make the most lovely sticky gravy. Then you put the hock in the roasting over, near the top to crisp the skin. We used to do the same with boned shoulder of pork.
The aga dealers do run open days, you don't have to buy an aga. It might be worth going to one to get a bit more of a feel for it.
Sorry to go on, but I love mine, although I know there are people on here who hate them.