FN,
The only restrictions on visual approaches to Edinburgh (from the south) are:
1. Not below 2000' (Edinburgh QFE - hence 2100' QNH) until crossing the coast. This means that aircraft positioning visually can legitimately be at this level well south of the estuary.
2. Join final not less than 5 Nm.
3. At no point be below the vertical profile of the ILS approach.
You can check this all out at AD 2-EGPH-1-11 [
www.ais.org.uk]; any other figures you may have to hand are - I can assure you - a work of fiction.