It’s unfortunate that the Mikrotik RouterOS manual on IPsec is not great – it’s sorely lacking in details and good examples, and what examples it does have are not well explained.
Recently I had to setup several Mikrotik RouterOS to ZyXEL VPNs and through I would document how it’s done.
A common problem with ADSL in the UK is that most connections are still using PPPoA. This means that if you want a computer to have a public IP address on one of these connections, you need to either have a block of IP addresses routed by your ISP to your router (at extra) cost, or you use a USB modem. There’s no real option for those folks that want to connect something like a SonicWall or any other firewall device directly to the line.