My mistake on the G-H V H2S eauipment. I was wondering the same thing about the fin marking.
Also being shot down in 43, kinda muddies the water for V1 raids.
The earliest reference from the RAF archive shows the following enigmatic report.
30/31 December 1943
10 Lancasters of 617 Squadron and 6 Pathfinder Mosquitos attempted to destroy a V1 site which had been missed on an earlier raid, but the markers were 200 yards from the target and, with the Lancasters' bombs well grouped around these, the site was again undamaged. No aircraft lost.
With this from 29/30 Dec
8 Mosquitos to Magdeburg, 6 to Düsseldorf, 5 to Leipzig, 4 to Bristillerie - a suspected V-weapon site near Cherbourg - and 3 to Leverkusen, 6 RCM sorties, 2 Beaufighters on Serrate patrols, 5 Stirlings minelaying in the Frisians and off French ports, 4 OTU sorties. No losses.
1 November 1943 reveals
38 Lancaster IIs - Nos 3 and 5 Groups - made the first large-scale test of the G-H blind-bombing device and attempted to bomb the Mannesmann tubular-steel works on the northern outskirts of Düsseldorf while the main raid was taking place. 5 had to return early and 2 more were lost; the equipment in 16 other aircraft failed to function leaving only 15 aircraft to bomb the factory on G-H. The device later became a most useful blind-bombing device when it was produced in sufficient numbers for a major part of Bomber Command to be fitted with it.
Now as 514 was part of three group, it is potentailly possible for the stripe markings to have been applied for these raids.
Source
Royal Air Force - Home