Problem going through PTP VPN onto LAN, and then accessing site-to-site VPN.

As the subject says, I've got a connection from External to LAN via P2P VPN (Windows based) - and then I'm trying to access an IP which is at another site, connected with a Site-To-Site VPN.

I can access it fine from the LAN (ON-SITE) but not from externally while VPN'd into the LAN -

I'm on the same subnet when VPN'ing and on site, so I dont think it relates to the site-to-site config.

When im connected by VPN, i'm guessing i should be seen as on the LAN - or am I!? - Are additional permissions needed on the Sonicwall?

Thanks