Windows + web-app document management / version control

I require somebody to design and implement a document management and version control system into an existing Windows network which includes web access. It needs the ability for documents to be uploaded, modified and downloaded from within the native Windows environment and from a web application with PHP backend. Access from other clients is also ideal so I'd like the PHP backend to operate as an API so that clients can utilise a common access method. It is to be used by standard computer users so cannot be complex/difficult to operate Some requirements - 1) Access from within the native Windows environment should be as seamless as possible and integrate with existing network infrastructure, group policy etc. Access should be from within Windows explorer 2) Web access needs to be to the point of providing a PHP class with relevant properties/methods to enable a hook to add/modify/view all data 3) Version control is required so a history log is kept and files can be restored to previous versions 4) Simple to operate for an average end-user 5) No need to check out the files before editing but a file can be manually locked to prevent modification by other users 6) The file server will be within the local LAN so distributed files are not required. No separate check-in process. Imagine an existing file server which now just has the ability to record history and versioning 7) When a file is uploaded the user has the ability to apply tags through the web-app to classify the file for searching 8) Full-text search capability for text documents (incl. PDF, Word) When you bid please provide an overview of your experience related to this type of work and a brief summary of the type of technology/method you propose. We can then discuss a milestone payment for the initial modelling/requirements phase where we can work together to scope the project and agree on specific details to get an accurate price for the entire project and partial milestone payments throughout the project.