Obviously I don't know your grandmother's financial situation but if it may be that if her own assets with her husband including her house are above the Inheritance Tax level, and the willed property remains in her name, it might have to be sold to pay an Inheritance Tax Bill if she is the last one in the couple to die. If she contacts the Executor solicitor very quickly she might be able to instigate a Deed of Variance which would transfer the property to your name now to avoid this risk. This would remove it from any risk that it might have to be sold when your grandparents die. What you then do with the property can be up to you and your grandparents to decide. The other risk is that if you grandmother is the last survivor of the marriage and the willed house is still in her name, it might have to be sold to meet care home fees if she needed to go into residential accommodation.
As your grandmother doesn't want a lot of hassle on this, I suggest you jointly get an independent financial advisor to ensure that her best intentions for you to benefit don't badly wrong through lack of professional advice or ignorance of all the pitfalls. (Of which there any many in this situation). Good luck. You are very lucky and it would be a tragedy if lack of professional adviced caused this very fortunate windfall to be snatched away from you.