About to use these products to repair some cracks in some external masonry, although I've not used them before, the process looks very straight forward. I've got a 4.5lt tub of the 'special Helifix grout', cost about £50 + vat, but a bit surprised it looks to me like a bag of OPC and a sachet of PVA! Now I'm sure Helifix would say they're 'specially formulated' materials, but sure looks to me like I'm being tucked up!! Anyone have any opinions on this?