Bybs performance is going to produce some (fibreglass) within a month or two apparently. Some dude in the states does them as well but not heard any experiences RE shipping to the UK. On the hunt for some as well.
If youre on FB theres a group called United Silvia Kingdom, it's pretty dead but there was a post on there a week or two ago which had Bybs and some US dude post on it. Groups not that active so wouldnt be hard to find the post