Hi Tony,
Not really an advert just me trying to give some guidance!
We carry out a lot of spray foaming jobs on total rip out and refurbs and the jobs are carried out very professionally. Spray foam like any industry is full of good and bad installers, it's just picking through the rubbish to find the one's that care about doing a good job.
I agree that as a refurb done in stages without ripping out, other forms may be better but we tend to insulate a lot of canal boats that have been completely stripped and the solution works very well, particularly for filling and sealing tight and curved voids without leaving cold bridging
Kind Regards
Richard