Thank you both, Phil and Derek, I will try the green Gripfill on some spare item. I feel that the Gripfill will fill the larger gaps and that more control over the welds be the result. So, I will give it a try.
Practice, practice, practice, as the saying goes. Here's another one, measure twice, cut once.
Phil, did you manage to get to the Air Show ????
Our Windermere holiday was a bit of a washout.....never mind, enjoyed the 'rest'.