A little ungracious DK? Monty has always sown his sweet peas in spring and had good enough results for him so it was good of him to respond to criticism and comments on the old Beeb boards and do a trial of sorts. He was very gracious himself in accepting that, so far, the autumn ones had done better but it remains to be seen whetehr the spring ones catch up by lasting and flowering longer into autumn.
As I've said, autumn sowing isn't an option for me and I can't be the only gardener out there with such problems. Plus which, I'd rather have sweet peas going on into autumn when i'm here to enjoy them than peaking in summer when I'm away on hols.
As with anything in gardening there are no hard and set rules except for certain very fussy and usually exotic plants. For the rest, we have to do what suits our situation, climate, soil, resources and needs. Luckily we have a wide variety of gardeners on here to offer advice from their own personal experience -which is what Monty does on GW.