Ok @Adam1989 hope this helps. These are all with tender.
22892 is tender one numbered 250, MTS sound and on board decoder.
20892 as 20892.120 but numbered 251, sound 6 pin decoder interface.
21892 similar numbered 251, sound but 6 pin decoder interface.
20892.120 as 21892 but numbered 250.
The ones without tender are 20892, 21881, 23881 but you did not appear to show interest in these, they have 6 or 10 pin decoder interface only 20892 has sound.
Info from LOK catalogue of LGB products.