A. This is one of the most commonly asked questions, but also one of the most difficult to answer without a detailed picture of the window in question or a site inspection. For example, if a leaded light panel is bowed either fixed or inside an opening casement, the only permanent resolution to this would be a removal and complete re-lead in the workshop.
If there are only 1 or 2 broken panes and they are on the outside edge of the panel they can usually be repaired on site. Whilst a little unsightly (the lead will ripple as glazing is removed and installed) it can be achieved and sealed again with cement or putty. If there are too many breaks or they are central (in the panel) then it will often require removal and restore in the workshop. Repair on and off site are obviously significantly different in cost so it is always best to send in photos and request for what you would ideally like and get an accurate quotation. Contact email@example.com if that is the case.