Need help with a Database Project

I am currently working for a company based in London who are looking to develop a large scale database approx 25,000 records and made available to multiple users online via a sharepoint platform because I happen to know a bit about ICT the task has fallen to me to research and develop a proposal.

The budget for this project will not be huge but should be enough to do what we want.

I have been spending some time doing research and am getting many coniflicted opinions. I would like to gain some further opinions on the potential of the following to do the job.

Database to be created in MS Access 2010
To cut down on maintenance and upfront cost use of hosted sharepoint (which version will foundation be enough)

In my research I have heard many people talking about issues regarding multiple users in access databases, how does this play in the 2010 version and coupled with the hosting via a sharepoint platform how will this affect the running speed of the database.

Currently all the information is held in Excel spreadsheets.

Will access be the best solution here or should i be looking at a larger SQL based platform

Thanks

Mike

What I have