Fixing draughty gaps behind skirting (photos included)

Dragon101

I have some draughts that come into the house from behind the skirting board. i took the board off and found some fairly large gaps where the plasterboard doesn't meet the floor (in pictures). When it is windy a very strong draught (or breeze!) comes through here.

what is the best way to seal this? I want to do a better job than just sticking the skirting boards on better.

The section shown is actually part of a 6ft extension of the ground floor to the front of the house. Hopefully this issue doesn't exist throughout the entire central wall but I will remove those boards to confirm once I am happy i can fix any issues I find!

In a different room but in the extended portion also I noticed that when i removed some wall lights that a strong draught was also flowing through the hole for the electric cables.

In general I have two questions: is there a good product that I can use to fill in any gaps in internal walls i find behind the skirting to stop draughts.

Is it normal to have such breezes flowing through internal walls anyway and if not is there a good way to rectify this? Even if the internal walls are sealed behind the skirting it must still cool the entire house as the walls will be colder.

checking the front of the house there are no noticeable gaps in the window frame but where the front external walls meet the driveway there isn't a "fully sealed" appearance. The house was built 1965 (with extended portion about 20 years ago) so it obviously won't be AAA standard. But we recently purchased it and I'd like to get it as insulated as possible in a cost effective manner before considering any of the expensive upgrades available.

vicwatson

Images not working for me

Dragon101

Thanks for letting me know. They seemed to work for me but then not when I checked on my phone using safari.

I've uploaded using a different web-browser to see if that makes any difference.

ive also created an album in flickr which should work better

https://flic.kr/s/aHsm7Xms99

Dragon101

for reasons unknown to me two of the pictures worked the second time (I think) and two didn't. The two that worked show the issue anyway so I removed the other attachments.