Vinyl flooring- How do I remedy a botched job?

[ClaraClara]

I did a good template from previous vinyl flooring. Handyman should have fitted the r-hand side to the nooks & crannies and pared off at the opposite and top sides of new vinyl. Instead, he cut off pieces where he shouldn't have thus mucking up the template. I think, with a bit of good advice, I can remedy the situation. I need to do some fine cutting/paring mentioned above. Scared of taking too much off. Any ideas? Or is it back to the shop and buy a new lot (expensive) and get the shop's fitter to fit?

ClaraClara