Parents' network currently configured as shown below. Two separate buildings sharing a single 300/100 fibre connection with a wired link between them. Building 1 has a Spark Smart Modem 3, Building 2 a SM1 with DHCP turned off. Main wifi and guest wifi networks running across both buildings. Works perfectly.

Alas, the wired link cannot stay. As such, I'm looking for recommendations for a 'wireless bridge' setup to replace the current ethernet link. So that the new configuration looks like this:

Considerations:

• No, I really can't use wired ethernet. I wish I could.
• The SM1 and SM3 are at opposite ends of their respective buildings, probably 50m apart.
• I don't mind if Building 2 has internet speed less than 300mbps (say, if the new wireless link is limited to 100Mbps).
• Devices A and B will sit inside their respective roof spaces (one roof coloursteel, the other corrugated aluminium) and won't have direct line of sight. It's not an option to mount them externally so that they do have line of sight. But they won't be far apart (less than 10m).
• PoE for the new devices is preferred.
• A seamless main and guest wifi network across both buildings needs to remain.
• There is no issue with wifi coverage at the moment so the new devices don't need to provide general wifi coverage (if they do, that's fine, but it's not needed).
• New devices need to be easy to install and set up (I'll be providing remote instructions), and require zero to very little admin or maintenance.
• Need to retain the SM3 and SM1 in each building as there are various wired things hanging off each of them.
• I want to do this as simply and cheaply as possible ($200-$300).

What should I use for new devices "A" and "B"?

 

1. Mesh wifi products?
2. Dedicated point to point wifi bridge setup?
3. Something else?

I like the idea of a dedicated wireless connection, but the products I've seen are all focused on longer distance line of sight applications, and are expensive.

Thoughts and suggestions are welcome - thanks in advance!