Previously working Windows 10 VPN connections to Meraki MX firewall via Meraki client VPN have been working fine. One morning user cannot establish connections anymore with the error: 
Can't connect to VPN
A connection to the remote computer could not be established. You might need to change the network settings for this connection.

All VPN server address, username, password, advanced VPN settings confirmed as working with no change.

Solution:  

1. Open Windows 10 Device Manager > Network Adapters
   
2. Expand Network Adapter and right click > uninstall all WAN Miniport adapters
   
3. Once all removed click Action > Scan for hardware changes
   
4. All WAN Miniport adapters should return
5. Test VPN again and connection should establish

New NBN HFC plans providing speeds of up to 1000mbps down and 50mbps up are now available. At the time of writing Aussie Broadband is providing the NBN Home Ultrafast plan rated at 1000/50 for $119 a month for the first 6 months.

Business class firewalls can provide more advanced security features and in the case of Cisco Meraki devices the  Advanced Security License provides

• Content filtering
• Google SafeSearch and YouTube for Schools
• Intrusion detection and prevention (IDS/IPS)
• Advanced Malware Protection (AMP)

These kind of features require processing power and often to the detriment of raw internet throughput, as such the Cisco Meraki MX64 and MX64W are rated at:

• 200 Mbps - Max throughput with all security features enabled
• 250 Mbps - Max stateful (L3) firewall throughput in passthrough mode
• 200 Mbps - Max stateful (L3) firewall throughput in NAT mode
• 100 Mbps - Max site-to-site VPN throughput

In testing this resulted in speeds of ~108Mbps down and ~35Mbps up on an Aussie Broadband 100/40Mbps plan

Speed tests on the newer Aussie Broadband Home Ultrafast 1000/50Mbps via a Cisco Meraki MX64 on Advanced Security License with Advanced Malware Protection (AMP) enabled and Intrusion detection and prevention set to Prevention and Security Ruleset resulted in speeds of ~250Mbps down and ~45Mbps up.