A video titled 'Amateur radio construction with Steve Hartley, G0FUW and Pete Juliano, N6QW' was recently posted on YouTube by the RSGB as part of their ongoing Today at 8 talk series.
The first part of the talk (1:09 to 35:30) is by Steve, G0FUW as he introduces the subject of making your own radios and circuits. This section is aimed at beginners and is a good place to start.
The second part of the talk from 35:30 to 1:17:00 by Pete, N6QW covers more advanced designs and is aimed at more experienced experimenters.
The Q&A session goes from 1:17:00 to 1:39:23.