As bizarre as this may sound. Apart from Sage 300 now (AFAIK), Sage themselves no longer integrate their own CRM with their own ERP / Finance Systems. 
You need to purchase 3rd party connectors or build your own. 

We did develop some integration with Sage One (SBC Accounting) many years ago. but the end user soon moved to xero, so we ended up building closer integration with xero for them.

The Sage Accounting API is quite well documented and we found it pretty easy to work with though.

As bizarre as this may sound. Apart from Sage 300 now (AFAIK), Sage themselves no longer integrate their own CRM with their own ERP / Finance Systems. 
You need to purchase 3rd party connectors or build your own. 

We did develop some integration with Sage One (SBC Accounting) many years ago. but the end user soon moved to xero, so we ended up building closer integration with xero for them.

The Sage Accounting API is quite well documented and we found it pretty easy to work with though.

>> Sage themselves no longer integrate their own CRM with their own ERP / Finance Systems

Not quite correct, Sean.  Sage CRM builds & maintain their own connectors for North America, Australasia, Spain, France & German markets.  Other, third party, connectors are also available for these & other regions.

Interesting.... for which finance systems?
Would be good to know as we're often asked which Sage finance system does it directly integrate with (not 3rd party)