well...problem is diagnosed...I noticed the underbelly coreplast was sagging a bit directly under the grey water tank...I used a bottle jack and some plywood to raise the sagged area back up to near level...went inside and turned on the kitchen faucett...normal pressure and flow rate at the kitchen sink...they will pump my tanks tomorrow morning so I will be removing coreplast and seeing what failed and allowed the tank to move...certified welders onsite and lots of steel tube and angle...should be able to fix it permanently over the next few days...
Thanks to all who contributed...
Regards
