I cannot tell you how pleasing I would find it if you were to make Catneuterer Towers your official address. It would be beautiful. ZOMG, you could have personalised stationery printed up with that on & everything! 
Mmmph, it all sounds very tricky. Perhaps you could ask your neighbour how they feel about cat-coiffing & poo-picking & if they're on for it take him in & (unless it seems he'd do better going back to the centre while you're away) leave him at Catneuterer Towers with the others? The work you do is truly inspirational-incredible & whichever solution you settle on, Simon's a lucky chap to have found you.
Winter - would a bit of emotional blackmail work on your DH? Am sure the Cats Protection people would be able to advise you about which cats would be happy to join your household - good luck persuading your DH to agree.
Yay for black cats though: tomorrow I need to join Instagram so I can send CP a gazillion pictures of my darling Jinpuss to (hopefully-maybe) use in their National Black Cat Day promotional materials. Cos he's incredibly gorgeous & I think it is only right to allow the world at large the chance to appreciate that fact. Yes.