Thanks - gone for velum dome style roof lights in the end, so will have all guarantees etc, advice appreciated.

I have three of these in a loft--side-by-side and quite large. Besides the summer sun baking in, my furniture was beginning to fade. The cost of blinds was pretty steep, so I opted to use light-cream drapery panels with a rod pocket sewn into both ends and thin tension rods to hold them taut. Works like a charm! I still have plenty of light--a softer, diffused light. And the light fabric reflects most of the heat. Plus, the UV damage has stopped. Another bonus--the fabric acts as an insulator in winter so there's much less radiant cold off the glass. A win-win, and the whole arrangement cost less than $100.

You don’t have the pitch to do a traditional style elevation. To be honest, a more modern design looks better and a more deliberate delineation of old to new. When we did our extension, the architect designed a sloped zinc roof but with windows upstairs, it’s practically flat so the zinc is not really visible from the ground level. We could have therefore saved with a cheaper material. Inside it has good height and I am very happy with how it turned out. Light is an important consideration. Originally we had smaller velux windows in our design but we settled on larger roof lights to improve the light. Again I’m happy we did that as the light in our north facing kitchen is great at all times of the year.

Anything is possible depending on your budget. Cost will depend on factors like type of skylight and your location, so I'd recommend getting some quotes from builders or window installers.