Gozzer
You are very lucky to be staying in Southend
And you have a great choice of where to eat in that village:
* Muneroy Tearoom http://www.muneroy.co.uk/
It is fantastic - especially if you like proper home baking and cooking.
The shop beside the Tearoom also sells some local produce like potatoes.
* Argyll Arms http://www.argyllarmshotel.com/
It does good value pub meals and also does takeaway pizza.
At the foot of Bellochantuy Farm road they often have a stand with their own vegetable produce for sale.
Muasdale shop, like the one in Glenbarr already mentioned, do a good range of frozen, local meat for sale.
And you can often pick up fish on the quay through the week, depending on what the boats have caught.
Another good place to eat is the Network Tearoon in Carradale, again for home baking.
Local events often have local produce for sale, so it is worth-while looking out for what is on - check posters in village shop windows.