Naughty buns not want to use a litter tray?!

Millie and Thumper are my only 2 buns not litter trained!!!
I tried litter training them when they were seperate with no success and tried again now they are together!
But everytime i put in a litter tray they dig in it and throw the tray away and tip it over, as if its a toy :?
also they dont ever just pee in the one corner of their cage they pee EVERYWHERE and when i let them out of there cage in the morning they pee all over the carpet! my mum and dad want to change the carpet but dont want wee all over it! :?:?:?
How do i stop them doing this?
My mum and dad arent putting wooden flooring down as its the dogs room also and the dogs prefer carpet!!

Need help as im at wits end and i am getting so stressed cleaning carpet every night! They are both neutered so why do they not like a litter tray?

giving them a high sided plastic box as a litter tray will help, mine like to dig too. Make it quite a heavy one so they can't tip it up & big enough for them to both sit comfortably. Make sure they have hay in the tray and a hay rack so they can munch and poo. Use something like megazorb, covered in hay in the tray and newspaper in the rest of their cage. If they poo or wee on the paper, sweep it up or replace it & put the soiled paper in the litter tray.

Don't give them too much space out of the cage to begin & lay down newspaper on the floor. Return any poos/soiled paper to the litter tray. Give them another litter tray outside of their cage.

Reward them when they go in the litter tray with a few pellets! If they look like they are going to pee outside it say NO, very firmly and return them to the litter tray.

Finally, how big is the cage & how long do they spend in it. trashing their cage may be a sign that they are bored. Most indoor cages are too small for two bunnies to be confined in for any period of time. Can you attach a dog proof run to it so they can run around all day when you get them a bit more trained?

They have a Ferplast Rabbit 140 with an attached run (which is about half the size of the spare room and other half is the dogs)
They have the run of the room most of the day, just at night they get shut in the cage/run area! They have loads of toys, cardboard boxes, newpapers to rip up, a doormat they like to dig at, toilet roll tubes and every suitable thing i can find! I want to give them a NIC set-up but they will pee everywhere!
Their daughter who is not yet spayed is in a NIC setup and is the best at using her litter tray and not ripping anything up! Why cant they be like her Grrrr.....:lol::lol::lol:
Im off to the shops later so i will get them an even bigger litter tray and so more of the wooden toys they like from P@H!!

I will try everything you suggested and all i can do is hope for the best
Thanks for the help its really appreciated :wave:

is their daughter near them? If she's unspayed her smell & the fact that she's close might be causing the weeing as they will be marking their space.