Welding skills aside, it matters not if you're a deep sea coded welder, the point you all seem to miss is, the fact remains that modifying a purpose built towbar negates any purpose design and build strength and mount issues applied. By altering a design which is then not compliant, and has not had load/stress factors calculated, there is a strong and inherant risk that other parts of the towbar could fail or compromise mounting points that were factored in at the start, so could even damage the tow vehicle. It's not just about raw pulling power. Once bits are welded There is not the opportunity to remove, come mot if it's an issue. There is also an insurance issue to consider, were something to go tits up.
To say things like, I don't care, know nothing about it, it was on there when I got it, as long as it looks strong and does the job is ludicrous from a safety or legal point view, but there we are.
Good luck with your choice bones. 'Nuff said.