The Buccaneer S1 was of course tested by A&EEE Boscombe Down.
To enable Buccaneer S1 to get airborne with a full weapon load, the fuel load was reduced and buddy buddy tanking was used from other aircraft types to top up after takeoff.
On HMS Eagle, 800 Sqn had a reduced number of Buccaneer S1 (10 instead of 14) and 800B Sqn had 4 x Scimitar F1 for tanking.
On HMS Victorious, Buccaneer S1 of 801 Sqn were tanked by Sea Vixen FAW2 of 893 Sqn.
This site shows a total of 21 (looks like 4 x prototype / pre-production + 17 x S1) Gyron Junior aircraft lost with crew attempting ejection - not all due to engine related problems.
Buccaneer