The link seems to be broken, so I can't see the architecture you are aiming at.
I disagree with numb-nuts - but I guess from his side of the fence (as an installer) he has a point!
If you are reasonably technical and methodical then it should be possible - depending what you are aiming at.
The Ubiquiti links similar links are excellent when used correctly. I have used them for broadcast radio studio-transmitter links where 24x7x365 operation without any glitches whatsoever is important. But in my experience to give reliable connection they need PERFECT line of sight - no bushes or even twigs in the way - you must be able to physically see the unit you are aiming at plus a bit more (Google "Fresnel zone").
Cyanide makes a good point - think about the data rate each camera will generate and perhaps statistically how often that will be simultaneous. Also remember that quoted throughputs of WiFi kits are the maximum possible with units very close, and typically total of both directions. S0 300Mbps link would be 150 each way absolutely max, and over a longer distance will gradually fall.
They claim up to 30km for a link but that's probably marketing hype. I know people who have used them at around 10km with no problems, and my experience was at 2km also with no problems. If you are UK based then buy equipment that can operate in the licenced Band C at 5.8GHz. The licence from Ofcom only costs £50 per year. That gives you more power (up to 4w ERP) and I'd hope it will have less traffic in that spectrum than Bands A and B. 2.4GHz would be untenable in most places except really remote areas.
Also if wiring will be exposed use exterior UV rated cable and self amalgamating tape covered by insulation tape. Another tip - get the entire set-up working on a bench - that way if it does not work when installed you know it's something physical wrong, not the parameterisation. Build the network one stage at a time checking as you go.