I use HiLevel for a lot of bits and bobs, especially reel seats. Not been charged VAT, but it might be because most things come in a small padded envelope.
I have recently bought some reel seats from Taniwha Rodworks on Etsy and have been impressed. Everything has arrived within 2 days
The website is not the best but the reel seats are lovely.
I bought one of there "Components kits" that consisted of handle, reel seat, guides and a winding check and I was pretty impressed.
They also do "sets" of guides that work out cheaper than buying individual guides, and they take care of the sizing etc. Also a handy guide to guide sizes on the site.