similar story when we first had our Bus. took screen out ok to replace perished rubber. guy came to put it back in" piece of ******* these", oh its that why you broke it then. to be fair it was a seal from er a mail order company and very hard rubber.. old chap round the corner with an old bus gave me a genuine vw seal and the rubber was so soft a plyable... so me and the Mrs fitted it ourselves. be confident and swear at each other alot helps too.
All the other windows are toughened glass - brilliant stuff - I've had both ends of a side window fitted and the middle bowing out 2" - not exaggerratinggg. Windscreens were toughened when our buses were made. Nowadays windscreens are laminated glass. If you treat it like toughened, it cracks quite easily.