Hi Crispin. A friend of Alisons had exactly this problem. They had her bike for repair for ages and wouldn’t respond to phone calls or emails. One call that did go through he claimed he was waiting for parts- but somehow she found out that parts had never been ordered. She ended up threatening a legal process and going in with a witness to demand the bike back. He then claimed illness. The whole process was very unpleasant.
That was 2-3 weeks ago. The bike is now Edinburgh Bike-though still not repaired- and still awaiting parts.
Not sounding hopeful for your friend. On her experience I wouldn’t leave a bike with them.