Crispy rhizomatous begonia - advice please!

Hi. I have some sort of rhizomatous begonia that I picked up from a garden shop 2 months ago (mid-May), and it is not happy. The larger leaves have gone brown and crispy and I'm not really sure why. It was not in direct sunlight, although my mom (who is an experienced gardener, though not with begonias) reckons that the sunlight it was getting was still too intense, so we moved it to a better spot about a week ago. I live in Edinburgh where it is humid, but based on what I've read on other forums, I'm wondering if humidity might still be the problem.

The pictures attached were taken this evening. There is some new, healthy looking growth that I really want to protect. Should I cut off the larger leaves and try to focus on the newer growth? If I do, should I repot? When I got it in May I repotted it into the pot in the picture, and the soil I used had some fertilizer in it. I fertilized it once more with a diluted solution and it perked up, so I don't think that caused the crispy leaves.

Does anyone have any advice for my begonia? I'm definitely a novice gardener and this is the first "fussy" plant that I've attempted to keep alive, so I assume that I'm making some sort of massive rookie mistake.

Thanks in advance for any advice!

 

I'm pretty sure begonias prefer shade?

 

yes too much sun , just snap the leaf off rather than cut it of from the main stem .

 

ok, thanks! the area we moved it to has moderate sunlight, as opposed to bright (but still indirect) light, so hopefully it'll be happier there.

Spruce, can I ask why I should take just the leaves off, as opposed to removing the stems and leaves from the rhizome?

 

I meant the leaf and the stem its doing no good and could introduce rot to the main stem , try and do a clean break if you can should heal over in a day

just keep the compost damp as to much water will rot the roots and the corm

 

Do you think this could be some kind of Begoina rex?

If it is, its growing out of character, it should have larger leaves and shorter stems.
I'd go for high humidity but fairly dry at the roots, they are easy to drown.

Good indirect light, but no sunlight at this time of the year.

I wouldn't repot, it wont help a struggling plant, more likely to finish it off.