I ordered my sofa with Sofa Workshop and they're brilliant, quality is amazing and it arrived 4 weeks before the expected - in theory it was supposed to arrive next week but I was told that with covid it would probably be delivered after Christmas so I was very surprised when they called me early November to book a date for the following week. Mine was ordered from their branch at Tottenham Court Road and Marcos was our advisor, very knowledgeable and patient.
I had a look at Heal's, Loaf and Sofas and Stuff, but couldn't find anything that suited our style. Darlings of Chelsea was very well recommended to us too but I didn't go the to check.
As for your question about L-shaped sofas still being fashionable, I ask you back: does it really matter? As long as you're happy with it and it suits your living room and family needs, just go with it! I'm an interior designer and I believe that we need to have a home that we love not a home that follows the current trends.