Fun decision Graham!
Look back to my Sony A7s pics in Flickr, go here, the last Pic taken with it -
https://flic.kr/p/DhtW9E
Never noticed any star eater issues with it, maybe the firmware is too old? Aint upgrading it!
I've started using it again with my new 10 inch scope and am very determined to get it working after seeing the early results. From my light polluted BY it grabs a heap of data in 2 mins and 4 with a 6nm ha filter.
But, and this is a big but- Sony's ASK is incompatible with any of the astro control software. I have to use 2 free bits of software to control and schedule it. And am currently trying to work out how to use my guidecam as the focus control cam, since I can't use autofocus software with it. No news about improvements in compatibility yet. Idiots.
If you get it modded, use an expert provider and be sure to that they maintain ability to do terrestrial and Wide-field shots, bad guys will fail that and the cam wont get focus for these targets at infinity.
Good luck!