Squawk7700,
In my opinion ATC should not have "offered" Special VFR.
It is the pilot's prerogative and if the pilot does not know about it then that is a good reason not to mention it!
Special VFR requires the pilot to be able to navigate visually:
By day, when VMC do not exist, the ATC unit responsible for a control zone may issue, at pilot request, a special VFR clearance for flight in the CTR, or in controlled airspace next to the CTR for the purpose of entering or leaving the CTR, providing
(AIP ENR 1.2):
- the special VFR flight will not unduly delay an IFR flight
- the flight can be conducted clear of cloud
- the visibility is not less than
- 1600 m for aeroplanes
- 800 m for helicopters
- for balloons, not less than 100 m below 500 ft AGL and 3000 m at and above 500 ft AGL
- a helicopter is operated at such a speed that the pilot has adequate opportunity to observe any obstructions or other traffic in sufficient time to avoid collisions and
- the flight can be conducted in accordance with the requirements of CAR 157 regarding low flying (see page 1.28 ).
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