Hi Shelley
I'm not a legal boffin but this is based on my recent personal experience.
Have you been assigned the lease? Unless you've been assigned the lease from the previous tenant (which is usually done through solicitors and the property's landlord), you won't be the current legal tenant (and in fact you may be in breach of the previous tenant's contract).
However, I have a lease on a shop but I wanted out 4 years ago. A friend tookover the shop and contacted the landlords to advise we wanted the lease changed (assigned) to her name (but this never actually happened). Long story but to cut it short, she stopped paying the rent. But, because the landlords had accepted cheques directly from my friend in the past I wasn't taken to court for the outstanding rent as apparently (I took legal advice), there was a chance that by accepting her previous payments, it could be said they had accepted her as the new tenant. Maybe this would apply to you. (Grey area I was told!)
(There again, if your lease doesn't allow you first refusal on a further lease then it won't matter if you're official the current tenant or not will it? There's an opt-out clause in our pub contract meaning the landlords don't have to renew it to us - this is an important clause but I can't remember its name, sorry)
What sort of relationship do you have with the landlords? Can't you contact them for a chat? And remember you can get 30 mins free advice from most solicitors - make use of it!
100% self repairing leases are usual on commercial premises from my experiences (3 premises) :cry:
It can get really complicated if the landlord wants to play everything by the book so do look into it properly.