It is always best to exercise caution with contracts. It is not unreasonable to ask your landlord or letting agent if you can take a copy of the tenancy agreement away to view for 2–3 days. This is often preferable as you will have time to read the contract without the added pressure which can sometimes be created by agents and landlords, whether willingly or not. Be persistent, even if they refuse, as it is not wise to sign unless you are fully aware of what is expected of you and what you can expect from your landlord.
If there is a clause that you do not understand or you do not feel happy with then you should seek advice in order to get it clarified. You can contact the Student Advice & Support Centre in the Student’s Union, the Citizen’s Advice Bureau or the University of London Housing Services (ULHS) private sector advice service to get confidential advice on contracts and clauses. It may often be the case that the clause is legitimate and a simple explanation is all that is required; however, ensuring that you get it checked will make sure that any potentially problematic or even illegal clauses are filtered out and brought to attention.
If the clause is excessively complicated and / or the wording obstructs comprehension then the contract could be in breach of its requirement to be in plain, intelligible English. If you believe this to be the case please, once again, consult with the Student Union or Citizen’s Advice Bureau. Once you are able to fully understand the clause it may be possible to negotiate a different wording with your landlord, rather than rejecting the contract outright.