I had such fabulous advice on my trees - can you please help with my border design?

[Namechanger0800]

Hi folks - I had a brill response to my plea for tree advice so am wondering if you can help me with a border I am working on?

Again as per back of garden we have ripped out a load of overgrown conifers so pretty much a blank canvas again, bar an overgrown camellia at the end of the border

Border is west facing, lots of sun, Sandy soil (I think) about 300x150 but is in a wave. I have read too much now I think so am confused about what and where to plant. I think I want a kind of cottage garden/ Mediterranean look

At the moment I have already purchased (but not yet planted) a load of English lavender with the intention to have it at the front of border making a low hedge - then a box ball to mark either side of the path ( edge of border). A bay tree for the back at the end. Happy with that - then I have purchased some hebes and euronymous with a view to them going towards the back of the border with the middle to be decided, but I can't seem to get the layout right with these. It looks weird - trying not to line them up but doing a wave looks staged as well- maybe I need something tall and wavy in between ?

They make it look so easy on garden rescue but planting stuff to look natural but not a mess is very hard . I've read the rules - tall at the back, small at front etc...repeat plants but it looks staged when I've set it out

Any advice or diagrams I can look at that shows patterns for planting up a border as I am boring myself and refusing to plant anything I've bought now because I can't quite get it right

Am thinking of a yukka as well at the other end - not sure if they are called that but they lay low to the ground without the trunk?? Or will this look jarring - so any help much appreciated !

Amelanchier is one of my favourites, can grow up to 15ft though!

I've read the rules - tall at the back, small at front etc...
That also applies side-to-side. Make the border look like a mountain (tall in the middle, smaller on the edges) or a range of mountains (repeat the small-taller-small shape).

I like a natural woodland garden look, so probably too "messy" for you. Basically I plant different sized trees, with shrubs in between, some ground cover and then something spilling over the front of the border like daisies, which I plant intending them to spell seed. I also have roses, climbers (honeysuckle, roses, star jasmine every metre or so along the fence (or anywhere I can fit them in realistically)

My only thought would be to consider a box alternative if you are in the UK. My neighbours have been hit by box caterpillar and it has destroyed their box in less than a week. Otherwise don't worry to much about the perennial plants you can always see how it goes and move things if you don't like it. They like to be lifted and divided so won't harm them. Do you have other plants in the garden you can repeat. I always think this pulls a garden together?