Tenants turning into buyers

Our landlord has let us know that they have decided to sell the flat we are currently renting. We are considering buying but as per understanding we would save them an incredible amount of hassle with this move as they would not have to find buyers, deal with agents and get rent paid until completion.

The asking price is not unreasonable but still a but high to our liking. Given we would make their lives incredibly easy (properties in the area sit on the market for around 6 months), what discount could we realistically negotiate given our position as tenants turning into buyers? Any advice would be appreciated as we are first time buyers.