SEB Research likes to express GBP shorts via options.

"Despite a negative equity- and commodities beta, Sterling has held up relatively well against the USD since the start of the Iran war, supported by a carry tailwind after the sharp repricing of the Bank of England. GBP has found itself in a “carry sweet spot” but faces downside risks regardless which direction interest rates move; higher rates risk denting the growth outlook and reigniting fiscal concerns, while a repricing of the BoE lower would erode Sterling’s current carry protection," SEB notes.

"With no obvious currency to short GBP against, downside is best expressed via a EUR/GBP call spread or a carry basket approach to isolate idiosyncratic UK risk while minimizing carry drag," SEB adds.