Hi Patchy,
From:
http://www.irishstatutebook.ie/2001/en/si/0600.html
“shop” means a structure used for any or all of the following purposes, where the sale, display or service is principally to visiting members of the public—
(a) for the retail sale of goods,
(b) as a post office,
(c) for the sale of tickets or as a travel agency,
(d) for the sale of sandwiches or other food for consumption off the premises, where the sale of such food is subsidiary to the main retail use,
(e) for hairdressing,
(f) for the display of goods for sale,
(g) for the hiring out of domestic or personal goods or articles,
(h) as a launderette or dry cleaners,
(i) for the reception of goods to be washed, cleaned or repaired,
but does not include any use associated with the provision of funeral services or as a funeral home, or as a hotel, a restaurant or a public house, or for the sale of hot food for consumption off the premises, except under paragraph (d) above, or any use to which class 2 or 3 of Part 4 of Schedule 2 applies;
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I think you may need a change of use on this basis alone.
In addition, there may be zoning requirements in the County or City Development Plan which apply to the site, including recent variations, local area plans, development controlled zones and the like.
The below link is an example of the latter:
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So really, you need to talk to your local planning officer on a first call basis.
If he says "yes but come in and talk to us" AND you want to put your best foot forwrd and not look like an interested amateur, appoint an architect to develop the design and draw up your plans for a pre-planning discussion.
If he says "no" then you have an uphill battle depending on his reasoning. Don't be discouraged totally, though, because sometimes the best locations are those that are hardest to get permission in.
FWIW
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