Installing soffit vents upvc and wooden

[mrbg07546]

I have a piv installed and wanted to get better ventilation in roof . I thought about installed soffits. Current I have a 1960s home with the old wooden soffit boards over boarded with upvc. I am looking to install soffit vents. Please advise me if this is possible. I have also shown a picture of my neighbours Upvc board so you can see what I boarded over. Additionally I have a loft extension done /0 years ago so there is still loft space but less. There’s a void leading to soffit. What soffits should I get

 

[Wayners]

Drill 70mm hole for 68mm push in round vents every 1000mm

 

[mrbg07546]

The loft area has a extension with a small
Loft void. Will it cause walls to get cold? I put a camera down hole

 

[Scally-Ho]

Are you 100% certain your 1960's soffits are wood and not asbestos?

 

[mrbg07546]

I checked neighbours. Who has other wide of semi detached. That looks like wood? Also it’s 1960s -1970 usually 1970s -1980 have asbestos