Yeah , I have had those days too , in the beginning I also always spotted in 'Wingtips' we arrived at BRU airport metro by train at 06:30 and we quickly rushed to a table (I thought to remember wingtips opened from 7AM)wich was not so hard around that time and we stayed until 1700LT. But the time I started logging was later , 1999 , but I already spotted earlier.
Anyway you forgot (or you didn't knew the type , airline , ....)to mention what G-BGDA was, it was a British airways B737-200Advanced in the 'South Africa' colors.
I can't tell you what exactly you might have seen but you might have seen this.
Sabena B747-300
Sabena A340-200/300
Sabena A330-200/300
Sobelair A300-B4
Eurobelgian airlines B737-400
Sabena Fokker F28
Sobelair B737-300/400
Sabena B737-200A
Sabena B737-300/400
Sabena DHC 8-300
Sabena ATR 72(?)
United airlines B767-300/B767-200
Aeroflot TU-154M
Sabena DC-10
BMI British Midland B737-300/500
BMI British Midland BAe Jetstream 41
DAT Delta Air Transport EMB-120
DHL Convair CV-580F
Onur Air A320
Singapore airlines B747-400
Singapore Cargo B747-400F
Cathay Pacific B747-200F
----OR-----
Air Hong Kong B747-200F
--
Electra DC-10
Saudi Arabian airlines L1011
RAM 727/737/747/757/767
Air Belgium B757-200
Aer Lingus F50/ BAe 146/737-300
Tarom B737
British airways B757/B737(200,300,400)/B767/A320
Virgin Express BAe 146/737-300
Air Algerie B727
DHL A300-B4F
DHL B727-100F
Cubana IL-62M
SAS DC-9
Lufthansa Express B737-400
Lufthansa B737-300/500/A320/A300
Turkish airlines B737-400/800 or A310-200/300
TAP air Portugal B737-300
Emery Worldwide DC-8F
DHL DC-8F
Cargo Lion DC-8F
Air Atlantique/Atlantic Cargo L-188 Elektra
DHL L-188 Elektra
Air UK F50/BAe 146
Sabena A310-200?/300
MEA A310
Air Mauritius A340-300(if you were lucky)
Corsair B747-300 (if you were also lucky)
United airlines B747-100/200 (if you were lucky)
AOM DC-10
Royal Jordanian A310-300
Egypt Air A300-600 or B747-300
American airlines B767-200/300
Continental airlines B767??? (already served BRU than???)
Saudi Arabian Cargo B747-200F
Saudi Arabian Cargo Lockeed C-130 Hercules
Air Algerie Cargo Lockeed C-130 Hercules
Aeroflot Cargo IL-76M
World Air DC-10
MNG airlines A300-B4
Pegasus B737-400 or 800?
Air France A320/CRJ/...B747? (if it was in the time that Sabena had strong co-operation bonds with Air France...they might have better sticked with AF instead of SR
Ghana airways DC-10
LAC Lignes Aeriennes de Congolaise B767-200(F?)
Air Gabon DC 10???B767-200??? or B747?
Air Alfa B727-200/A300-B4
Air Cameroon B747-200
and soooo many other things....I do forgot a lot , but it's just a quick list , a short review...on the good old days...when I was a small spotting boy
I particulary like this ramp shot of that time...it gives a good view of some heavy traffic on that day.
UA 747
MK 343 (Air mauritius)
RJ 313
MEA 310
UA 762
and think about the pictures you might ever have seen on the old commercial-board of restaurant 'wing tips' in the airport building wich shows a UA 744 and TG 744 in one shot , just awesome , all on the B-dock.
Now you can't have seen this ones all on one spotting day , but these are planes you MIGHT have seen that day. I can't give you exactly all planes from one day , but you might remember some planes with this list.
Best regards: Yannick