Partial screening suggestions

Hello
I'm looking for suggestions for somewhat sparse/airy, wildlife/insect friendly, evergreen plants (probably shrubs) that are needed to fill in gaps in a mixed front hedge. We want something that provides a bit of a screen especially at ~1.5 to 2.0m but also allows some light through and enables us to look through it a bit. Plants that are already there include Cytisus 'Porlock', Tamarisk tetrandra and a Corokia cotoneaster. I've perused RHS plant finder, etc, however I'm don't know how dense some plants are or whether they could be thinned out, the pictures I can find tend to just show close ups of flowers. There is a young Ceanothus 'Puget Blue' in the east border which I gather is considered quite sparse in habit when mature; I'd be fine with different cultivar for one of the spaces if anyone knows of a suitable one. The location is south facing behind a ~90cm wall, limestone clay, open aspect (so exposed at times). Thanks in anticipation.

 

Provided your soil does not become consistently waterlogged, a Buddleia could provide an airy option, popular with wildlife and remaining semi evergreen over winter, easily pruned to fit gaps. A variety like Black Knight or Royal Red might suit.

 

Thank you, very much. I do like the look of both of these. The soil is sticky when wet however there is a slight slope to the north and never any standing water. Alliums don't return in the other the south faciing border nearest the house hivever lavenders really thrive so drainage seems ok overall.