The Guardian Media Group’s operating loss of nearly £70m in the past year is a startling figure. GMG has enormous cash reserves, but the yawning maw of unprofitability snapping seventy million pounds of flesh out of a business in a year could quickly begin to feel terminal. It may be the biggest challenge of the Scott Trust in the last 80 years to figure how to modernise the GMG advertising model without compromising editorial values — if those values haven’t already been compromised.