Graham
I have some files by both Nicholson and Simmonds and they have served me well. I usually shy away from the no name unless I'm looking for boat anchors.

I have no idea of the brand name Tome Feteira made in Portugal. Offhand I would probably have more faith in them than no name. Perhaps someone else on board here has heard that name before.

Edit to add:
I decided to google the name to see what I could find and here it is.
http://www.tomefeteira.com/Founded in 1856 by Joaquim Tomé Fèteira, File company Tomé Fèteira, is today a modern manufactering plant with an established name producing products of hight quality.
For almost one and a half centuries research and development has taken place in the production of files and rasps.
The experience gained by Empresa de Limas União de Limas União Tomé Fèteira in the manufacture of files and rasps is being used to develop new metallurgical products with Collar - Tomé Fèteira quality.
The constant search for improved quality and the rigorous inspection of each Collar - Tomé Fèteira product ensure that are of a standard unmatched anywhere in the world market.
Those where the principles which make the wel known Collar brand demanded by buyers and users all over the world.
With the ever growing demand for our products, the original plant has been developed into todays modern factory.
In more than 65 countries where its products are sold Empresa de Limas União Tomé Fèteira has a network of representatives, agents and distributors giving efficient backup to buyers and users of Collar - Tomé Fèteira products.
So I guess that these files are probably as good as any that you will find on the market.

Cheers

Don