I'm packing with nowhere to go ? what is a realistic offer ?
What is it worth to you to have this disruption to your life and work? You are entirely free to refuse any viewing by the EA or landlord as it would be a breach of your rights to an exclusive and peaceful enjoyment of the property.
Will you lose business / income if you have to be at the property for viewings - how much will it cost you?
Under circumstances where a landlord buys out the lease of a tenant, I would normally suggest a month's or two rent and if early on in a lease, also moving expenses. However, as you have been given you 56 days notice, and already some of that has been used up, it would be unrealistic for the landlord to offer more than one month's rent (and probably not worth that much to him) as you will have to vacate now in about a month's time.
Even if the landlord had a buyer, it would take probably in the region of 6 to 8 weeks before contracts were signed and the sale closed so the landlord still has time to play with. However, his main point of interest at present may be getting your permission for viewings as legally, the landlord is only entitled to enter the property for periodic inspections (or repairs) by appointment at a time convenient to both landlord and tenant.
If you require a reference for your future landlord, if you are not willing to allow viewings you may find that the landlord is not willing to give you a reference of any real value.