SVFR is nevertheless a practical compromise on otherwise rigid flight rules in particular situations, this flight seeming a classic candidate – of special relevance to this case is that for 10 years there have been a simplistic VFR vs IMC arguments with no mention of the SVFR option let alone any discussion. Yet again, an intuitively obvious line is being summarily dismissed rather than modest efforts being made to establish what exactly were the intentions (why not chase up an ATC contact?).
You say <<and in any case the Mull is not in such airspace>>; well, their intended path was at low level across the approach to the Macrihanish runway – and the critical turn not too far from it. I would have thought that ATC would want to know how the a/c knew where it was precisely if landmarks on the Mull were not clearly visible (which they were not) or SVFR conditions would have had to apply (eg. No other a/c in local area until ZD576 clear).
In answer to your question <<And what speed had the a/c been 'holding for the flight' then?>> I refer you to:
Mull of Kintyre -Analysis of Available Data
8-7D20-DS S-03 06, Enclosure 4
Dated: June 18,2002
By James Mitchell of the Boeing Company (available on the net).
Anyone interested in this case would be well advised to read this document (this is not the simulation).