In 2019 the farming museum that my local Guild meet at had just restored a flax break and scrutching machine. They asked if the Guild members would like to use it. I got a raised bed made in the yard, as the area chosen was prone to getting pretty wet. Seeds were purchased from Wild Fibres
http://www.wildfibres.co.uk/ and broadcast sown late April 2020. On 1 August I harvested by pulling up the plants, roots and all. These were stooked to dry.
I saved the seeds that I removed from the flax (rippling) by using a home made item from a piece of wood and 5" nails, held in a vice on the work bench. The seeds and bolls went everywhere so that is an area for more thought next time.
I retted the flax in a dog paddling pool, changing the water after three days. I had intended leaving it for five days but a veterinary emergency meant that I forgot about it until day seven. I hung the flax bundles to dry on the front of a stable then stored them in our old grain store.
Nothing happened until the Guild had a flax day, this summer, due to someone getting a bulk load of Berta's Flax
https://www.facebook.com/groups/279258827044398/ I am still not being a social person due to covid so I sent some of my dried flax for them to study for processing. They each kept a strick and returned the rest to me. I still have the rest of the flax straw stored to use at the museum when I next go.
That is the home grown story so far. I also have some of Berta's flax and several other stricks from various sources as I like spinning flax. Maybe because flax was the first fibre that I spun that worked out right.