Hope your Grandad is Ok Neilly.
When my girl was pregnant with Coley the nurses and midwives were more or less guilt tripping her into breast feeding. I resented them a lot for that. We were also told that the kid could grow up obese and a bit slower if not breastfed.
Cole has been bottlefed from week one, counts up to ten and strings coherent sentences together. He can also distinguish plurals, all at 2 years, 2 months.
There may well be health benefits to breast feeding mothers but I'd love to see the evidence concerning bottle feeding making kids a bit slower.