There has been a suggestion that the attack on Tobruk planned for 21 November 41, but cancelled because of CRUSADER, contained an amphibious landing element (see e.g. this thread at the Comando Supremo forum), similar to Operation Venezia, the attack on the Gazala position in May 42 (see here for Kampfgruppe Hecker). The evidence on which this claim is based is a sentence in Hinsley’s British Intelligence in World War II, Vol.II, the official history.
The Evidence Basis
Having looked at the relevant evidence on the Axis side, I must say I can not find anything showing such a plan, and it is not included in the relevant planning by Panzergruppe Afrika or XXI. Corpo Armata.
I did however find that elements of the Tobruk garrison were alerted to the possibility of such a landing on 15/16 November (e.g. ‘D’ Squadron 7 R.T.R.). So this leaves us with evidence only from the British side that such an attack was planned, but no evidence from the Axis side to that effect.
Extract, War Diary 32 Army Tank Brigade, Tobruk Fortress, 15 November 1941. TNA WO169/1303 – Rommelsriposte.com Collection
Regardless of the planning situation, there is also no evidence that there was a material basis for such an attack. No landing craft were present with the Regia Marina in autumn 1941, and the German F-Lighters only arrived in December (see this link). There were also no parachute troops in theatre, other than the Italian Carabinieri parachute battalion, who at the time were guarding the rear sector in the Djebel Akhdar (see this link). It is quite possible that the Arab agents put 2 and 2 together and arrived at 17, when they became aware that Italian parachute troops had entered the theatre.
My conclusion is therefore that this was a real British scare, but not a real Axis plan. If that conclusion is correct, I find it baffling that the British official history would repeat such a claim, given that access to German plans would have been had quite easily for the writers.