Bit more info, not good.
The 2640B has a web interface to enable snmp.
The 2640R is I think deliberately crippled for TalkTalk., and can't even have its firmware changed - leastways the firmware files on D-links site(s) are for an 'older' version and wont install.
Telnet revealed loads of stuff, including how to set every snmp parameter except how to turn it ON.
So, if you want SNMP, get the 2640B.
I WISH these manufacturers wouldn't de-feature routers.