They changed the plans, can i cancel

[ricohuk]

Hi All,
We were forced into exchanging 6 months ago after paying a depost. Along with the nightmare of an expired mortgage offer we now find that they have changed the garden plans.
There was a flat south facing garden which wasn't over looked and it had a great view of the gower valley, it was a prime buying motive.
We have just done the meet the builder thing where we found that they raised the house by three feet to lessen the slope leading up the drive, this wasn't an issue but that's what they did. The knock on effect is that there now needs to be a terrace built where the patio is and stairs built in to a lower level garden. This was supposed to be a normal flat, back garden with a patio, not the split level thing it's going to be.
The plans the builder is working from are not the ones we signed on exchange.
Can any one please advise on weather or not I can cancel on these grounds and have my £8000 deposit back?
Thanks....
Rich.