I worked with the launch of G2 in 2005 (and had to wear a heavy wool black kilt to boot!)... it was launched late spring in Western Australia - with temperatures in the low 30s at the time. Over the following months, the mercury reached 42+ degrees, and I still wore it.
What I found was the warmer it got, the more comments I collected. On my skin at least, the radiant amber notes seemed to project well and compel others to comment.
Though I'd imagine some couldnt carry it off in such weather (depending on application), I found it very enjoyable, as did those around me.
I'd imagine a British summer wouldn't prove as warm, but I guess it ll comes down to body chemistry. If you can source a sample or wear some on a hot day, let your best judgement guide you. Good luck!