How can i unblock my toilet and stop the waste coming up into the shower?!!?

Very unlikely to be the feed pipe from toilet if it as described 'Banking up'. Disconnect the shower from the toilet pipe and find another drainage point it's healthier.

As Peccavi says check the inspection chamber the soil pipe feeds in to if full be ready to beat them back with a stick, now check the next manhole if clear you now know blockage is between manhole. if the second one is also full it's out towards the main sewer. Drain rods using the worm attachment if you feel you have the stomach to tackle it. Tip: Duck tape the rod joints and only TURN THE RODS CLOCKWISE turning anti-clockwise can undo the rods if the tape doesn't hold and then you are in trouble with a dig up job. Once clear add boiling water and coustic soda mix to the drain, a fairly strong mix. but use rubber gloves as wet caustic powder/crystals burn skin.
Failing that DYNO ROD

Bob
December 2009

All the drains will come together at some point - in fact I have to unblock my own in a few minutes but they are not as bad as yours - it may be that you have a blockage in the foul water downpipe or (I hope not) in the inspection pit that it drains into. If you're confident investigate yourself otherwise reach for yellow pages.

If you do take the lid off the inspection pit - stand well clear - there may be a small fountain.

Good luck...

Peccavi
December 2009