From what I have read on the independent satellite sites you can but will need a dish between 2,1 and2.9 mt diameter depending on which part of the algarve you are

Wiz

Is there anyone currently on the Algarve able to say what the current situation with the TV is.

I'm not in the Algarve but am in Germany and the loss of the channels you mentioned will affect me. From what I understand installing a larger dish may not help.
You may have seen the following link
http://www.bbc.co.uk/blogs/aboutthebbc/posts/Changes-to-BBC-Satellite-transponders-in-2013

We have already pretty much lost Ch5 already with just intermittent reception during the day and nothing at night. We are still receiving all other channels.

I don't know whether this thread on the albufeira.com forum will help
http://www.albufeira.com/forum/uk-tv-satellite-issues_topic7636_page1.html

I am in Praia da Luz as I type. There has been a loss of some channels but only a few. All CH5 stations have been lost except for CH5 HD which can be received by a sky HD box with a suitable card. CH4seven has also been lost.as well as some ITV channels. for a full list go to http://www.lyngsat.com/Astra-2F.html. After satellite 2E has been launched and brought into service there will be more stations lost but which ones and when is pure speculation for now