Curtains - very curved bay window - help!

[RoSEbuds6]

Hi there, we have a very curved bay window made from 5 smaller windows, underneath is a large curved radiator. At the moment we have horrible grey venetian blinds which do the job, but I find depressing.
It seems that I have either the option of spending a lot on bespoke curtain pole and then having access to eyelet curtains, or using a cheaper flexible curtain track and then having less curtains available to buy. Is there another option?
We have an airbrick under the window with causes a draught so I'd like some thermal lined curtains.
Where can you buy a good selection of curtains? I have looked at JohnLewis, Next, M&S and Dunelm but because DH quite likes the blinds, I don't have a limitless budget to get some made.
Any suggestions, thoughts, pictures, links or cunning plans?
Thanks in advance

We have these, I’ve just taken them down for redecoration and was looking to replace them as they are fitted to the ceiling and need a pelmet to cover the tops iyswim BUT they work beautifully and I just googled them to discover that they are solid brass and probably £££ (they were here before we moved in) So looks like I’m stuck with the pelmet. I do like the look of yours JulietMadeChutney, is there a special fitting so the curtains go over the brackets?

@RoSEbuds6 -

Rule of thumb is to measure the pole from end to end and multiply by 2 (maybe 1.5 for eyelet curtains.) This gives you a guide for the total flat width of curtains you need.

So, if that 350 cm is the width of your pole requirement you would need between 525 and 700 cm width of fabric in your curtains.
1 pair of the ones in your link would be 2 x 167cm = 334cm, so yes - you would need 2 pairs.

Thank you @rosegoldwatcher. Can’t wait to go to John Lewis to see some curtains in the flesh! So hard to get an idea of the pattern and colour on line.