Looks very like slug damage, the little blighters.

Try setting out a beer trap at the base of the plant

Is it in a pot? Copper tape is very useful for deterring slugs. Sheeps wool too although that's pretty expensive. Slug pellets are harmful to wildlife.

ASDA do what they call 'Organic Slug pellets', I'd give them a try. I'm getting masses of slugs & snails with the wet weather here & they overstepped the mark when they started grazing my courgettes.
With a climber you'll need to check hiding places behind the plant too.
To help with damping off on seedlings try watering with diluted chamomile tea or spraying lightly with 3% hydrogen peroxide

Thank you everyone. following your advice I’ve checked for slugs or snails and used a beer trap but the holes have started appearing much further up the plant - as far as 2-3 foot and now they’re really tiny holes like pin pricks so I’m wondering if it’s soneting else - any more suggestions would be very much appreciated

The damage on the upper part as you describe it could be from Thrips. As a matter of fact the small white spots on the leaf in your photo is from thrips whereas the holes in the same leaf are caused by a separate culprit, most likely slugs. As the saying goes ...good things come one at a time and trouble comes in legions. So I think there are two problems going on at the same time.

Don't underestimate slugs willingness to climb up walls/fences to get to the juicy bits!
This is a very good site:

https://www.gardeningknowhow.com/ornamental/vines/morning-glory/pests-of-morning-glory.htm

Thank you everyone!