Anne B what you have quoted from the act refers to routine inspections and conducting opens at the end of a tenancy.
Unfortunatley the owner has the right to sell the property or put the property on the market at any time during your tenancy, the real estate agent has to give you 'reasonable notice' this is not specifically defined in the Act. If you have a fixed lease the letting or estate agent cannot enforce you to leave until your contract has expired. If you are looking to rent again it would be advisable to be compliant with the letting agent as you will need a reference when you rent your next property, if you also develop a good relationship with the real estate agent they can also act a referee for you. It is unfortunate that you have experienced this so soon into your tenancy and owners let their properties out for various different reasons it could be that they have found their investment too financially draining or their own circumstances have changed. Regards