Thank you for this! My other UK-relevant fabric shop links are below.

Have bought from and would recommend:
https://www.fabricsgalore.co.uk/
https://sewmesunshine.co.uk/
https://kayestextiles.co.uk/
https://www.empressmills.co.uk/
https://www.backstitch.co.uk/
https://www.clothhouse.com/ (expensive but nice fabrics, many Indian or Indian-inspired)
https://jhannaltd.com/ (Irish linen, limited colour range though)
https://amothreads.com/ (deadstock, very varied, some good bargains)

Have only had a sample from so far, but seems good on the basis of that:
https://www.slubbedprints.co.uk/

Haven’t yet bought from but they look interesting and their websites don’t suck:
https://www.midlandtextiles.co.uk/ (large range of paisleys, brocades, Indian wedding fabrics, etc)
https://www.thesilkroute.co.uk/ (silk fabrics in small pieces or by the metre, also sari silk yarn)
https://www.etsy.com/shop/inphyneetee/ (African fabrics)
https://www.fabricuk.com/ (large selection including silk dupion in many colours)
https://www.africanfabric.co.uk/ (artisanal African fabrics actually made in Africa)
https://www.raystitch.co.uk/ (good selection of small tools as well as fabrics)
https://lamazifabrics.com/
https://thenewcrafthouse.com/ (deadstock fabric with fast turnover)
https://www.rainbowfabrics.co.uk/

And a UK pattern-printing recommendation: https://savvysewist.co.uk/