First: That's a Micro Ma 505 series 1 arm, I believe. Its an excellent arm and quite valuable. Even the headshells go for substantial money. And the cartridges are good, so you made out very well. Vinyl Engine has the manuals and so on for the arm.
If my memory is correct, the BD 103 had a 12 inch platter unlike the 2 and 2a. The 2s had a motor that was suspended on looped rubber bands and used an O ring as a belt. If the 103 has a similar setup, you could try it with a loop of thread -- if the motor is as compliantly mounted as on the 2s, you don't need the compliance of the belt, and you might be better off without it (I tried thread on my Micro Seiki 1500 a decade ago and never looked back -- dramatic improvement, and at a cost of less than a cent). Vinyl Engine also has the manuals for some of the Connoisseurs.
Connoisseurs look cheesy, but Sugden put all the money into the steak, and as little as possible into the sizzle, and their tables sound dramatically better than looks would lead you to believe. Clean and relube the bearing, get the motor mounted correctly and either get a belt or use thread, and fire her up. Do not sell it at your wife's tag sale. :nono::nono:
I feel strongly enough that I have, for the first time, added smilies, though these are frownies. And just in case anyone is confused, the Sugden of Connoisseur is a different Sugden than the Sugden of the highly regarded electronics firm. The turntable Sugden was something of a workshed genius, and came up with a stereo system for records before the 45/45 system was introduced, and was one of the first with a stereo cartridge, made by bolting two of his cartridges together at 90 degrees to each other. Wacky but effective, and cheap.