I'm here are you missing me? It's bloody mental here ATM
Wool doesn't shrink but backings do but face fibre can be a contributing factor.
I've seen this carpet before in nursing homes usually with the same urine odour problem as Geoff has had, the belt and braces approach is the best way like Geoff has done if you try and skip or cheat procedure you may as well get the staff to do it with a rug dr.
Shaun