That is an older Sidney lathe that probably does not have herringbone gearing. Not by any means a deal breaker.
As for a service manual or parts manual, there are none that I'm aware of on Sidney lathes. You might look on the "Vintage Machinery" website for any catalog reprints and also Tony-lathes over in the UK also. As far as I been able to find out, the company is not in business anymore. Nor has it been bought out be any of the other companies out there. There are people out there that have these old lathes in their shops.
Ken