Engenius ENH200 & ESR9850 network issues.....

Hi all,

OK, I'll try to explain our bridge as accurately as possible, let me know if you need more info to help me out, this is driving me crazy.....

ESR9850---hardwired--->ENH200#1---WDS--->ENH200#2--->4port switch--->ENH200#3---WDS--->ENH200#4--->5port switch

Customers internet connection is in his house, so the ESR9850 is located there. First ENH200 is mounted on chimney facing the first barn approximately 400' away where we have installed a second ENH200. These two are set up in WDS bridge mode. The second EHN200 is plugged into a 4 port switch mounted in the first barn to allow internet access for web-based monitoring of equipment there. From the 4 port switch, we have plugged in a third ENH200 set up in WDS bridge mode with the fourth ENH200 on a second barn, which is approximately 1500' from the third ENH200. We have set this chain up because of obstructions between the first & fourth ENH200. Router, first WDS pair, and second WDS pair are set on wireless channels 1,6 and 11.
We first had both bridges set up as AP-CB, but had to change to WDS because of DHCP issues
The 2 problems I am having now are:
1) internet connection speed at the second barn is extremely slow, even though the first few weeks of operation after setting it up WDS was no speed issues what-so-ever.
2) every so often (totally random periods) the router needs to be reset, because we lose all connectivity.

I hope this all makes sense, I don't claim to be an expert on wireless networking at all, I have done tonnes of basic bridges for web-based monitoring of our equipment, but this is the first time I have set a bridge up for access in multiple locations. Any input would be greatly appreciated.

Anybody????