Gainsborough Crystal passage set

I dont sell, and have never seen gainsborough hardware before, but today a customer had asked me about a handleset that they have installed on a door, in a house they're just moving into. It's a crystal passage set, and unfortunately when the builder was putting the latch in, he didnt have the common sense to put it in with a 2-3/4 latch, or longer, and the woman is scraping her knuckles on the jamb every time she opens the door. My suggestion is the most obvious one, put a lever on there...

I took the knob off and saw that the construction is pretty basic, and it looked like all the springs are in the latch. is it possible to split a knob/lever in a gainsborough set, without changing the latch? does a gainsborough lever-strength latch go both ways, and will it work (realistically) with a knob...

Or is Gainsborough hardware not worth five cents, and I should just sell them something else? To be honest when i took it apart, it looked pretty flimsy, so I'm wondering, is it even worth it to bother?

Gainsborough locksets are very popular here in Australia. They are 'basic' grade three locks, but come with a grade two price tag. Depending on the model, you can swap over knobs for levers, but I'm not familiar with the 'crystal' model name (USA ? ). I would just replace it with a lever set that you can get locally. I have a customer with over 2,000 round knob Gainsborough entrance sets, with tie bolt 127mm backsets, all master keyed with Lockwood 6 pin keyways. Gainsborough have just decided to stop making these now, and have completely changed the design of their locks so nothing is interchangeable, including the cylinders, and I can't get parts for these damn things anymore, and the locks are only 5 years old.