OP, if you’d like me to take a look at insurance for you, i’m in this sector. DM if you want a chat.
As it’s a fairly recent fix, firstly, insurers would want to know the root cause with written evidence. Check for a structural survey identifying damage and cause. In this case, sounds like the tree but, you want confirmation of this from a qualified surveyor/engineer. Secondly, detailed evidence of the remedial works with information on monitoring periods post repair. Info on warranty for the works and info on who the remedial work was carried out by.
With all the above, you shouldn’t have a problem getting insurance. It will limit who will offer terms, you’ll likely have a higher subsidence excess to start and, you will be paying over the average as a result for insurance.
With evidence of the above, i’d be happy to purchase a house with previous subsidence/underpinning.