What does your Provisional Tenancy Agreement say? I think there is a usually a clause in which it says, "If you don't sign the real thing by a certain date, you will forfiet whatever provisional deposit you paid and you have to pay both side's agents' fee"
So your choice is to NOT sign the real lease, and pay the above, or sign the real lease and PAY ALL OF THE LEASE' RENT if you signed the standard fixed one year lease, i.e. 12 months' rent, PLUS agent's commission on your side, i.e. 12.5 months rent.
Technically you can't even have someone just take over your lease unless your lease specifically allows it, as the landlord may decide he doesn't like this alternate tenant. That is, unless you do it under the table - you let someone else live in it, you collect money from him, and pay the landlord. This is technically sub-letting and usually not allowed in most tenancy agreements, but you can do it under the table but you will be responsible for all the alternate tenant's misgivings even if torches the whole place down.
The 2 months' deposit has nothing to do with it. Even if you forfeit it, the landlord could still sue you for the full 12 months' rent due. If you don't pay, he files with court, freezes your bank account, etc. If he cannot find a bank account of yours, he can apply for your bankruptcy and you won't have a job if your company is reputable.
My suggestion will therefore only be:
1) Just live in the apartment and commute to work
2) Don't sign the real tenancy agreement and lose whatever you have already paid under the provisional with the agent's commission penalty.