Landscaper/Groundwork recommendation - retaining wall job

[Pupp]

Am looking for recommendations for someone to handle a leftfield retaining wall project - it's effectively a garden wall but has to retain a hefty level difference (c. 2m less any batter that can be achieved atop over maybe a 12m curved run), after excavating a bank.

It is important to maximise the realised level ground area and needs to look reasonable when done (rustic is fine; overly engineered not so). Vertical sleepers, small gabion baskets, and even interlocked piled steel sheeting has been suggested - I quite like the latter but am not sure how domestic it could ever be made to look and it will be pretty visible. Planning is not an issue as it is PD in this location/application.

Purpose is to make a wasted banked area into a useful courtyard/driveway, so not a pretty pretty garden job, nor civil construction; sort of half-way house.

Suggestions welcome; thanks