Can personally attest to luckily avoiding being crushed by WTI/Brent mean-reversion spread trading. I had a 4 lot position that I halved which then eventually made my losses back and about 200 (aggregate) ticks profit. Even though I made money I probably shouldn't have gotten in the trade.
Europek.. there is a medium term gilt future you can use which is roughly 5y duration. very illiquid, but the option is there for you since you are in a long-term macro set up.. there is also a short term duration gilt future as well. i use both all the time for long term strategies. .. bid ask spreads "rarely" touch so.. just use a program to execute automatically when b/a spread narrows to a "somewhat" favorably slippage level. if you want to be active.. forget about it.. daily-plus time frames only do to lack of current participants. & just one quick thought although you already know this.. uk shorter term durations can really move too! good hunting