Ending a Scottish Short Assured Tenancy early?

[xu5]

The lease aggreement my girlfriend and I have on our flat is for 18 months due to end at the end of March 2013. We are thinking of ending early to move back to the family home so that we can save for a deposit. The contract does not state what happens if the Tenant wants to leave early.

After a quick search I found something saying that if the lease is over 6 months we would need to give 40 days notice which sound fine. Is this correct? Is it upto the Landlord whether he will accept notice given? Can I expect my deposit back if I terminate early?

Cheers.