I do know quite a bit about loft insulation
@Pam123 in a previous life I was qualified (well technically I still am in that field)
through insulation surveying and energy assessments /carbon reduction etc..
when you talk about "spray insulation" are you referring to blown loft insulation, that is the nice fluffy cloud like carpet on the loft floor (sometimes this is jyst an alternative to rolled out insulation)
or are we referring to spray foam adhesive that used to sometimes be sprayed on to the underside if the pitched roof as insulation (horrible stuff)
and believe it or not there are still companies out there that will spray the adhesive foam to the underside of roofs
if you let me know maybe on that I can advise