The Behringer Ultra-DI has been around for ten years or so - we have four that we use in all kinds of applications, mostly for feeding video cameras or remote amps from sound mixers.
I think I have one...and right now for the life of me I can not find it. I think it is like the Boss DI-1, except with XLR in.
Hmmm..how about the Jenson/Radial JS3? Would that work?
Features electrically isolated XLR I/O, a direct throughput with ground lift, and 2 transformer-isolated outputs. Has a 30dB pad, delivers 48V DC phantom power for microphones, has a ground lift, and has common mode noise rejection up to -100dB at 60Hz.
Here's mine. Don't know if it will fit your bill .. but it works great for me . .and it is real cheap! LOADSA XLRs and jacks and faders and .. al sorts. I really don't know how they do it for £78GPs