and contoneaster (or is it boxwood) and lilac(the heart shaped leaves?), and hedera...Plus the campanula. I'd say you've hit a jackpot! looks very promising.

I am pretty sure that this is Berberis, not boxwood. I did not plant it, but the leaves turn bright red and fall off in winter, so it's a pretty safe bet to assume that's what it is.

does it have thorns? I've had berberis before and was even so brave as to move the plants from an established location...as I recall the spine tips break off and leave little 'slivers' under the skin...It's a good deterrent in traffic areas...
cotoneaster has berries and is evergreen,

no, no thorns and definitely looses its leaves