A guy at work blew my mind when he explained that old lime mortar (any age) can be scraped out of a wall, put in a bucket with some new mortar and it turns back into fresh mortar.
It's completely recyclable!! Old tech isn't necessarily bad tech. He gave me a further 15-20mins on how great lime is (e.g. breathable, adapts to ground settling & loads of other things I've forgotten).
Anyhow, that cottage looks beautiful / brand new. Impressed at your skills.