Phal Orchid suffering from sunstroke

[supersheep]

I think my orchid is suffering from sunstroke! So I'm wondering what I can do to help it recover!

It recently lost its flowers, so I cut of the flower spikes and moved it to a different room - one which is warmer and has more sunlight. I put it on a south west facing windowsill, as this gets more light than its old spot.

I've put an orchid on here last year, through all of summer, and it seemed to thrive. But I think the recent heat wave we've had in the UK has been too much for this orchid. I noticed after a few days the leaves had these very white spots!

I moved it straight away, but now it seems to be very worse for wear. One of the leaves has fallen off, a few others are turning yellow and one is a deep, greeny/brown colour now and very soft to touch. One leaf is still green and firm, apart from a big white spot on it. There was a new leaf coming, but this has just completely shrivelled up!

The crown is looking a bit strange too. Where the roots touch it, they're a strange greeny browny black, but feel firm to touch. Where the base of the leaf which is a funny colour (the greeny brown one) reaches into the crown, it looks almost browny black. I'm worried there might be rot there, but it still feels very firm to touch.

One side of the plant has roots that look very shrivelled up, though they still turned green when I watered the orchid today. The other side has very green, plump and healthy looking roots.

I've attached a couple of pictures to try and help. But I'm not sure what to do for the best with it now. It's a very pretty orchid, so I want to try and save it. But I'm not sure if I need to do anything, or just leave it be.

Any help or advice would be much appreciated!