Thorn beta 5s have a aluminium canopy, and a acrylic bowl. Thorn beta 5s usually run 26/ 35w SOX, but SON versions were available, but they are rare. Thorn made these in top-entry and side-entry and they made  a few different designs for the canopy.

lido car park, Guildford 

this thorn beta 5 is on the lido car park, Guildford. This one has the 2000s style thinner canopy and it is side-entry. It runs on a 26/ 35w SOX lamp.

Here, you can see that the lamp is bent in the lamp holder.