ZX Spectrum +2 (grey) restoration

I had a grey ZX Spectrum +2 recently upgraded/modded with the regular recommended mods summed up in Adam's Vintage Computer Restorations:

#1: Fix the video output issues associated with the factory ZX Spectrum 128k+2. #2: Fix the audio balancing issues associated with the factory ZX Spectrum 128k+2. #3: Replace all the electrolytic capacitors on the mainboard and tape board. #4: Replace the voltage regulator and power connector. #5: Service the internal tape deck. [#6: Refurbish the power supply.]

My motherboard is a Z70700 Issue 1, made in UK at the week 47 of 1986.

The late Ben Versteeg of ByteDelight and others among the community mentioned that for the Z70500 Issue 3 *all 2N3904 transistors are mounted incorrectly* - meaning that for TR4, TR5 and TR7 the silkscreen markings are inverted and therefore you need to inverted these for a jailbar-free video output.

Initially I didn't have these inverted, since I saw no reports for the problem on Issue 1 machines. I had therefore these visible jailbars on RGB. Inverting these corrected the issue that was, as far as I am aware undocumented and only mentioned for the Issue 3 boards.

I'd like to give note to the community, that if you find yourself repairing or upgrading such an unit, Z70700 Issue 1 made in UK motherboards also need those transistors inverted.

If you have some experience with those boards, please let me know your thoughts on the matter.