The Switch by Beth O'Leary 

When overachiever Leena Cotton is ordered to take a two-month sabbatical after blowing a big presentation at work, she escapes to her grandmother Eileen's house for some overdue rest. Eileen is newly single and about to turn eighty. She'd like a second chance at love, but her tiny Yorkshire village doesn't offer many eligible gentlemen.

Once Leena learns of Eileen's romantic predicament, she proposes a solution: a two-month swap. Eileen can live in London and look for love. Meanwhile Leena will look after everything in rural Yorkshire. But with gossiping neighbours and difficult family dynamics to navigate up north, and trendy London flatmates and online dating to contend with in the city, stepping into one another's shoes proves more difficult than either of them expected.

Leena learns that a long-distance relationship isn't as romantic as she hoped it would be, and then there is the annoyingly perfect - and distractingly handsome - school teacher, who keeps showing up to outdo her efforts to impress the local villagers. Back in London, Eileen is a huge hit with her new neighbours, but is her perfect match nearer home than she first thought?