We have the film fitted, the guys left about half an hour or so ago. My first impressions are that the reduction in solar gain through the gable is absolutely massive. It's not been a particularly hot day, but the difference when you open the front door and feel the heat of the sun, compared with standing in the sunlit area of the hall with the glazed door closed is enormous. You literally don't feel any heat from the sun coming through the glazing at all. By this time of day, in weather like this, both the floor cooling and the MVHR cooling would be running (floor cooling comes on at 22.5 deg C, MVHR cooling comes on at 23 deg C). Neither have come on yet, and now it's well past 4pm I don't think they will.
The stainless steel Sentinel film does make the entrance hall very slightly darker, but that's partly due to me having got used to it being very bright in there. It's far from gloomy, but the reduction in visible light is noticeable. The impact on privacy is high, at least in daylight. This film is a very effective "one-way mirror", and prevents anyone seeing in from outside almost completely. I think this may take some getting used to, as from inside you can still see out very clearly.
The 3M film in the bedroom hasn't really had a chance to show any effect, as it was fitted after the sun had shifted around away from that wall, but it has very little impact on the light level in the room, but also provide less privacy. I should know tomorrow morning how effective it is at blocking solar gain, but if it performs as the thermal images of the samples suggest, then it should be equally as good as the front gable.
In terms of external appearance, I'm a bit surprised to find that I prefer the reflective look of the stainless steel Sentinel film over the plane glass. To me it enhances the appearance of what is a fairly prominent feature at the front of the house; not something I was expecting.
It's early days, and it will take some time to assess how this film performs over a range of weather conditions, but right now I'm very pleased with it, it seems to perform far better than I expected and has shown that I was mistaken in thinking that the gable glazing wasn't a major contributor to the over-heating problem. I was considering just the area of floor that was being heated by the sun coming in through this glazing, and what this film has shown is that it significantly reduces the temperature of the inner glass pane - this is now near-room temperature, and much cooler than the inner pane on the windows that don't have the film applied. Clearly there must have been quite a lot of heat being conducted and radiated from the inner glass panes of this glazed area, and that was contributing a lot more heat than I had thought was coming from this area.
If the weather is cooperative I'll try and take some photos tomorrow - the camera batter was flat when I tried earlier and I don't have a charger over here.
The cost was a bit less than the price Peter Starck quoted for his gable glazing, but still quite costly. It took three chaps around 4 hours to do the 5 fixed panes and the glazed door in the gable, plus the two panes in the bedroom window, and they hired a scaffold tower locally for the day that added to the cost. Having seen the process I don't think I'd want to attempt to DIY it, as the job is made massively easier with the proper film roll holder, dispenser and cutting/slitting machine they use. Plus there is no way that you could do a large window on your own, it really needs two people just to handle the film.