Kong,
Below is copy of post sent to Glen Fraser, also in the UK, last night. I have seen the Item extrusions and they are first class. Just to give you an idea on price, the 40 x 40 mentioned above works out at about £8/metre. It is a truly extensive range they have and available in the UK. I have the Alumas catalogue and that looks good too.
Glen,
If you're looking for extruded aluminium in the UK, try the Item range from mbsystem in Derby,
www.item-international.com or, Alumas in Chorley, Lancashire,
www.nisltd.com/alumas
The Item system is a little expensive, German but excellent quality with every imaginable fitting available. The Alumas is similar, a little cheaper and not such an extensive range.
All the best,
Mike