S am Kelly admitted there had been some nights of broken sleep as he led a two-year project to restore one of Salisbury Cathedral’s treasures, a stained-glass window by Edward Burne-Jones and William Morris . “It would be wrong to say I didn’t lie awake sometimes,” said the head glazier. “You are working on something that is very precious and if it fell on the floor, it would be very bad.” Happily, the 6.5-metre (21ft) tall “Angels” window did not hit the floor. The restoration has been hailed a huge success and this week the artwork will be celebrated and rededicated at an evensong service. The window was designed in the late 19th century by the pre-Raphaelite artist Burne-Jones and Morris, the textile artist and poet . Sam Kelly, the head glazier, started as an apprentice at the cathedral 40 years ago. Photograph: Finnbarr Webster In the century and a half since, water ingress, condensation and the deterioration of much of the painted detail led to the need for restoration.…