From my own experience and that of other members of the forum it does seem to be the ABS
that is the cause of the problems.
I got a 2nd hand ABS pump and fitted the lot to cure my problem, this meant disconnecting all of the brake pipes etc, other members of the forum have successfully just changed the ABS
to cure their problems, none of the fixes I'm referring to have required the
to be "electronically introduced"...they worked fine.
If I were in your shoes (maybe your husbands would fit better
) I would go down the 2nd hand
route and give it a go...even if that didn't work I would fid an alternative to paying out £525 one way or another
There is more info in the thread below...the fun starts on page 2.
Laguna II - ABS not working but no warning lights ?
Good luck & please report back on the outcome.