Serac greenhouse

Does anyone have a Serac greenhouse?
I have had one  for for about 15/20 years and it has stood up to all the gales that could have been thrown at it.
(If anyone watches the Beechgove Garden in Scotland they have one on site)
The problem is that now the double walled synthetic which is used instead of glass is not letting the same amount of light in.
My question is...can this covering   be taken off and replaced with glass.
I am in my late 70`s and really have no idea as I am not a practical person so perhaps there is someone out there who has one of these greenhouses and could advise me.