Do not under estimate the stress involved in achieving your rights to the letter to the law.
Legal entitlement of going to the far extreme of your rights as either a landlord or tenant results in untold stress for all sides.
Far better is to reach compromise.
If the landlord needs to sell, they may be able to sell to another landlord and keep you in place (so ask the sales negotiator)
The sales agent has a vested interest in a vacant property, so ask if they do rentals and try to prioritise you as a tenant on one of their other properties
The tenant may not have enough funds to secure a new tenancy, so ask the landlord if they are willing to help fund this.
In reality, the landlord needs to make commercial decisions, helping you fund your move will be less expensive than going to court for eviction, so don't think asking them for financial assistance is a ridiculous idea. Infact, I am surprised this hasn't been offered to you.
From the tenants point of view, waiting for the ultimatwvoutcome of court and bailiff eviction is very stressful at all stages, and you have no control over where you end up living.
Likelihood of poor (or no) future landlord references, CCJ poor credit rating will make future decent housing options unlikely. Rehoming a pet and looking at possible separate accommodation for adult children will increase your control over options significantly.
So ultimately compromise and cooperation on all sides will lead to the most beneficial outcome for all concerned.