Filling gaps in beech hedge


There are a couple of gaps at the base of a beech hedge between the end of my garden and a neighbour. I'd rather not be looking at his compost bin etc - any suggestions as to what I could plant to fill the gap?
I'd like to plant as close to the hedge as possible, be evergreen and not slow to grow. Approx 1m high I'd guess. The hedge is north facing so this spot would get very little sun (even less when the leaves grow!).
The second part of the post is regarding planting a shrub in front of the hedge. I'm thinking Escallonia apple blossom or Kalmia Latifolia. Both currently in pots waiting for the right spot to plant out. Which would be best in this spot - or would both / neither be ok? I'm aware the kalmia needs acidic conditions and believe both really prefer full sun? Many thanks.
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I don't think Escallonia would be happy there - it does like a bit of sun Andy
Some of the winter flowering shrubs like Osmanthus burkwoodii might be fine - preparing the ground's the vital thing, as Tetley has said.
Mahonia?
I live in west central Scotland - not where that photo is...
Fairygirl, unfortunately I've already got a mahonia to the left of the viburnum in the picture above
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So maybe the kalmia is better in front of the hedge (can put the Escallonia somewhere else).
For under the hedge itself, choisya is interesting, I've been googling a bit and sarcococca would seem to work as another option?
Sarcococca is a good idea too - they're not very quick growing in my experience Andy, but it may just be my conditions here.
Another alternative is a simple frame to put a climber on.
I live in west central Scotland - not where that photo is...
Some of the Eleagnus might be ok too - need to beef up the soil probably, and anything planted will need well watered and mulched because of the hedge.
I think I misunderstood your opening post Andy - I realise now you're looking for a gap filler and another shrub in front.

I live in west central Scotland - not where that photo is...
I'll look at pyracantha and elagnus - also walking around Harlow Carr at the mo', what about skimmia or would any ferns get big enough to fill the gap there? Looks like I've got some choice
It's ok - I'm easily confused Andy!
Skimmia can get chlorotic in the wrong conditions, so it largely depends on what soil you have. There are ferns which would be happy enough there and they often establish quite well. Ones for dry shade are what you probably need to look for as there'll be a fair bit of competition for moisture. Dryopteris springs to mind, but they might not get tall enough for your space.
I live in west central Scotland - not where that photo is...