advice on paint durability

I need to repaint an area of exterior wall under some ground floor windows which is badly flaking - probably no more than a square yard - and have found a small can of dulux 'feature wall'. I quaked at the prospect of buying the minimum quantity of masonry paint which would of course have been more durable but horrendously expensive for the area needed.
There is the added concern that the dulux is intended for interior walls but my question is: Can I reasonably expect this paint to last for a year or so by which time a more comprehensive decoration scheme is likely to be undertaken?
The guy at B&Q said he thought the paint would run in the event of rain. Is that really likely?
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<bob> wrote:

Normally stabilising solution needs to be applied to a flaking surface prior to applying any type of paint. Dulux feature paint is an emulsion meant for indoor use only. I don't think it will run in the event of rain, it will probably flake off during the drying process.
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wrote:

- thanks for replying.
It was a fine day (as usual!) so I took the plunge and slapped on the paint soon after my post. In fact I'd made a fairly thoroughl job of removing the readily flaking paint to leave a reasonably stable base which I then washed with sugar soap so I'm keeping my fingers crossed. Will post back if I spot any disasters.
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