Two of many, and ive had personal experiences with them as well.
I gave my local branch a 4205 and asked them if they could fit a new crystal which i supplied (Thats before i invested in a press) "Come back in 30 mins" was the reply.
Upon my return the guy showed me the smashed crystal which he had taken out by breaking it with a hammer, and then told me the new crystal i had supplied was too big in diameter and wouldnt fit.
I suggested quite calmly (unusual for me) that if he prised the retaining ring off, the crystal would press out easily without the use of a hammer and he would find the new one would fit.
New crystal fitted, i left with disgust, when i got home and put on my glasses i found the chapter ring was out of alignment with the dial.
You have been warned.