I'll be buying from KJN KJN - Suppliers or Aluminium Profile and Accessories since they do a 45x90 profile unlike Value Frame whose closest is 40x80 profile. I went with bigger is better, also from reviews I've seen on here about their good service and accurate cuts, I'm sold.

Don't for get to order all the extra connecting elements like T nuts and screws when you place the order with your chosen supplier. Also if you go with profile rails rather than supported rails you need to check the maximum socket head screw that will fit in the rail pocket, as you will have to get appropriate T nuts. For the profile rails I have, I found an M6 thread will fit but its head is fractionally too big, so had to use M5. For connecting ali extrusion profile with other I'll be using M6 Screws and nuts.

Hope it helps, Adil