Morning Baz.
Seems a bit odd. Even on a new one the underlever was not that stiff when I bought mine. Many of the components were hand fitted so I suppose someone might have swapped an underlever between rifles for some reason or another but if they did & it was that stiff you'd have thought they would have done something about it. Conversely if they had a very loose underlever I can't really think someone would have tried to close the flanges up......but then if they did I suppose they could have overdone things. But they are pretty solid so if a someone didn't quite understand what they were about I could see it being overdone & possibly marked as well but if there's no marks then it's still not to say someone had a go at closing them up. Opening them up a bit might not have been so easy. Maybe they thought it would "run in" rather than working on the insides of the flanges or the underlever who knows. Can't think Webley would have let them out the gate like that.

But there again is it binding on the flanges or is it the pivot thats tight?