thanks so much for the replies everyone, they have been rather helpful.
there are 2kw of solar panels on a 45 degree sloped roof facing SEE (south east east) they are spaced off of the roof on their frame by about 5-6inches. this is on the roof of a normal 2 story house in the UK
they rarely reach maximum wattage output though the most ive seen is about 1.65kw from them.
my initial idea was a few fixed mirrors in my front garden to give the panels a bit more juice in the afternoon when the sun's lower on the wrong side of my roof. with this itd be pretty easy/cheap to install (i could diy it) and due to its rudimentary/poor design it would negate overburning the panels.
from your replies though i doubt there is much i can do that would cost less than just adding more solar panels.
keeping them cool was something i hadnt thought of/know about, however im not sure how effective adding ducting would be.
sadly there is no more space on that side of the roof. on the other side are 3 skylight windows into the loft. meaning id need probably 3-4 seperate frames to hold them all. plus the whole ball ache of paying someone to do so.... scaffolding etc etc.
plus as this new array would need a new inverter as they are pretty much at a 45dgree angle facing NWW and im guessing wouldn't work very optimally linked into the old solar string array.
i could quite easily fit about 120watts of "flexible" panels onto the skylights/windows. seeing as they are movable i could work out some sort of limited tracking for them (opening the windows at the correct angle
i know fitting panels behind glass is a big no no due to heat....but maybe a bit of spacing and the poor uk weather would alleviate this. ive had a crappy 12watt panel set up this way for years, charging a battery for my lights in the loft conversion and its been fine.
ill do some more investigating and see what is within my grasp. (i was thinking about getting a small wind turbine instead
but im not to sure about planning permission nonsense etc)
if you do learn from your mistakes, i should be a genius by now.