[Mike Phelan]

Well done, Mike. One of the later G8s. I agree fully with Rich about the pushbutton unit; they must be like hens' teeth now.

I would definitely change the electrolytics and set up the HT and overvolts pots on the PSU, and check the balance coil on the line panel so the BU205s share their current.

Check that there is a diode from chassis to one end of the BR100 diac (across the charging capacitor) to prevent HT flutter when there is no other reason for this.
Later panels had it on, I used to mod them all to prevent having to replace the diac every other week!

Looking at the colour bars, all I can see wrong is a slight purity error and the usual hum bar from photographing it - was there a reason that you were suspecting the decoder was off alignment? There isn't a lot to align apart from the RGB drives and B-Y quadrature, if the ref osc is locked OK.