Good quality, adjustable impedence step-up transformer, budget £400

I've been running a Graham Slee Elevator EXP for some time now, most recently with battery power (2 x 12v lead acid, to give 24v). This seems to run for weeks on a relatively quick charge so it can't be consuming a lot of power ... it's also very nice with the Koetsu, into the C-J EV1 ....

In a previous incarnation of kit, into the tube phono stage of an Audion two-box pre, I settled equally on an active step-up rather than a SUT, at that point a Klyne Audio SK-1, which again gave me more of what I wanted (and less hum .. the arm I had at the time on the old LP12, the Alphason HR100S, was hard to keep quiet).

But still I'm curious to compare the Slee with a good passive SUT setup, matched for the Koetsu Red K (5 ohms) but preferably with 40 ohms available too for a bit of cartridge flexibility. I'm keen to settle the matter (within my budget at the least, some of the uber-SUTs being out of the question).

So .. anyone got a decent adjustable SUT for sale? My absolute top whack budget is £400, as I'm not selling the Slee for quite a while (basically till I'm sure which could be months - and maybe not at all if it wins the head-to-head) ... though actually I'd rather spend a bit less if possible. (Rubbish time of year and all that).