can you get one of those telescopic brushes? I think they can go up to 25 feet
Alternatively, lob some snowballs up there, once you create a small gap and it starts generating electric, it should heat up the rest of the panel to melt it
The heat escaping via a loft hatch will not be sufficient to penetrate through the roof tiles, jump the gap between the roof and panel, and warm up the panels to such an extent that the snow will melt.