« Reply #1 on: Yesterday at 08:44 »
Your post is a bit confusing as you don't explain where all of your ancestors at great grandparent level are from. Plus you said your grandfather was born in England but half Welsh through his parents who were from Swansea.
If you use my example below then you would be 25% Welsh if both grandparents are Welsh but only 12.5% if only one of them was Welsh.
Armitage, Atherton, Barton, Beck, Bradshaw, Brumfitt, Chetwin, Conalty, Connolly, Connor(s), Davidson, Hilton, Hoey, Johnson, Jones, Knight, Lester, McDonald, Molyneux, Morris, Pownall, Rushton, Spark, Stanley, Tunstall, Welsby, West, Wharton, Williams, Wilson, Windridge, Windstandley