ETX!!! They are a rip-off. Their main business is spread betting - or ripping customers off. They clear through Macquarie who I have on very good authority have terrible support and terrible software.
Try Marex in London, or may be Newedge if based in the US. We used to use Marex - they are pretty good. Fortis may also offer LME.
I think TT now have LME connectivity which is good news for everyone.