want to replace dwarf conifers 4ft.for something colourful low maintenance but same size

Leucothoes, hardy smaller evergreen hebe varieties (but be careful what you choose) Santolina, Lavender (if its sunny), Nandina domestica Firepower. Deciduous small shrubs Potentillas, Spiraea Goldflame, Berberis thunbergii atropurpureum

parahebe, there is a rockery hypericum that isnt a monster,
helianthemum [rock rose]
many of the heathers & ling [Calluna and Erica] will do this too. tree heathers, cant remeber the latin name.
Azaleas / Daphne [some are very slow growing so would suit for many a year]

welcome to GoY too.