Blazer, search for the Impossible?

[Beacauseisaidso]

For several years have been looking for a casual blazer that I can wear with jeans. So far so good.
Except I have narrow shoulders (am 5ft 2) am a portly 16 and large of bossom.
I can't wear double breasted for above reasons, ideally would like a longer line if possible.
At this point I would consider paying a reasonable amount as after much searching am yet to find such an item.
Any ideas oh resourceful Mumsneters?

Have you looked at Whistles? They do a single breasted, heavy duty jersey blazer which they repeat every season in different colours.
I think this is the link
It looks quite short on the model but was longer line on me, at 5'3.
I never bought it so don't know how it wears and washes but I eyed it up for a long time.

I also think Zara is pretty good for tailoring - far better quality than most of their other stuff.

Bear with me on this one but have you tried Evans? I'm a top heavy size 16 and found two blazers there! It's not somewhere I ever look either

Thank you.
I know that shoulders are too narrow for Zara, plus they tend not to go up to a 16.
Will have at the whistles jacket, I vaguely remember trying a blazer from there, where the shoulders were an issue too, but can't be sure it was that specific style. Will give it a try.
Thanks again