You are right to be suspicious. Learning organisations claiming spurious links to Cambridge, Oxford and (to a lesser extent) London abound, in the belief that people believe that they have some link to the prestigious universities in those cities. They don't and some are absolutely c**p.
TEFL has no national qualification awarding body (as far as I can find) so it sounds like it a pot-luck as to what you get.
Here's some useful Q&A with a link at the end to the website I got the info from. You might try Googling ‘CELTA TEFL’ BM
What TEFL certificate has the best name recognition?
The Cambridge CELTA. The Trinity CertTESOL is probably in second place, followed by the SIT TESOL Certificate, but that can vary depending on what country you want to work in.
Are there any international accreditation bodies for TEFL certificates?
No. The main guarantee of quality of the most well-respected courses (e.g. CELTA, Trinity CertTESOL and SIT) are the standards and reputations of the organisations that provide the certificates (e.g. Cambridge ESOL, which is part of Cambridge University and Trinity College London, a UK-based exam board).
How can I compare two (or more) different TEFL certificate courses?
The most important thing is recognition of the qualification. If you can find job ads that specifically mention one of the qualifications, that is probably the one to go for. If not, contact schools that you are considering working for (or random schools in an area that you are thinking about) and ask which they would recommend.
How can I tell if a course is really equivalent to a CELTA or not?
In terms of worldwide name recognition, no course is really a CELTA equivalent. However, when employers ask for "CELTA or equivalent" they mean a course with at least 100 hours of instruction and at least 6 hours of observed teaching practice. They are also likely to prefer a course that is well known (e.g. one that has been around for a long time and is offered by many course providers), and is accredited by a respectable university or exam board.
http://www.tefl.net/