I think cleaning the oven is probably one of the most hated jobs in the home.
I bought some revive power paste a while ago which is good for a lot of jobs around the home and it brought my oven up a treat.
I've recently seen on t.v there's something on the market where you pop you oven shelves in a bag and leave to work, then use the product on the inside of your oven as well, not sure of the make.
I swear by hob brite on the top and I now put a reusable oven liner on the bottom,also to keep my glass door clean inside I put a sheet of foil this works great when using the grill inside my oven, def a handy hint off a friend