Can anyone help me with my Monstera Obliqua (or possibly Adonsii)?

I purchased 2 of these plants on ebay about a year ago and potted them up. Being in the UK, they are being grown as houseplants. Although the existing leaves were a decent size, and close together, immediately the plants started producing these long, creeping vines with tiny, distantly spaced leaves and extended internodes. Here's the one that I've left alone, you can see the 'vines' trailing in front of the book case:

Not much like the pleasantly trailing plants I'd seen online! Is there anything that can be done about it?

I read somewhere on here that climbing aroids produce an enzyme once they attach to a support, causing them to produce larger leaves and shorter internodes. So I planted the second plant around a coco-fibre pole and cut back the long vines. Almost immediately the growth habit changed drastically!

Annoyingly this plant has developed an odd problem with its new growth. The leaves are opening all dead and brown inside. It's not at all like the kind of burning you sometimes get if a plant gets too much direct sunlight; it's the inner part of the leaf to unfurl that's brown, like it died before it opened:

The plant gets plenty of light. I am not using any kind of fertiliser. The soil is a compost / perlite mixture, and I allow it to become dry to the touch before watering. I also mist the plant daily. I cannot see any evidence of pests or disease, other than this.

Does anyone have any idea what may be causing this? I've never had a problem like this with my M. Deliciosas. Any help gratefully recieved!