I had my attic done with spray foam last year. Not by this company but with the same foam. There are a few things to make sure of...
Firstly make suire they can produce you a NSAI cert for the product they recommend.
Make sure they quote you for the breathable foam.
Get a reference from someone that they did work for.. speak to them if you can...
Ask them if they are going to seal your gable walls as well.
Ask them if they seal the wallplate
I have had very good results with mine and I was the only house on my row that didn't get frozen pipes this year. people came to my house for water
House is definately warmer and held the heat much better. I can still notice the warmth the next morning even before the heating comes on. I've definately reduced my heating bills but 50% is prob a little too big of a claim... prob more like 30-40 but definately a big improvement
I think I paid around 18 per sq m + vat
I recommend the product highly