Ignore long winded post about bikes - I'm rambling.
I've been trying to do the sums and it looks like it'll cost me £3k to replace my bikes and put in a little extra home security in the form of a ground anchor set into concrete and that'll be cheap as I know someone who'll make me one.
Dolly had been completely rebuilt with better everything, plus all the bits that you need just to push the pedals round. When you start to add it all up the figure gets bigger very quickly.
I found a replacement for Bob and Roberta @ Evans for £750 but then I need pedals and different tyres and lights and pump and lock and bottle cage and spares and tools and saddle bag to carry this stuff. Bloody tools were in the bikes plus spare tyres and stuff.
I'm just glad that I was lazy and didn't fix the gears on both bikes and Dolly had a little squeek. 
I'm doing agitated leg wobbling at the moment.