Address Locator From Drawing On A Map for Ireland & UK

I require a solution where a client can come on and select an area by drawing a map and it generates the address including full postal code. Basically running a query and they can then upload their letter and mail merge the address file that it generates. Addresses need to be generates in csv or xls ready for mail merging. Below is an example of a similar service: [login to view URL] [login to view URL] We need if for UK and Ireland so it 2 different databases. We also would like to add in the DMA District Metered Area database which generates addresses for water mains. Basically if engineers are working on a certain water mains network and they enter the DMA it should produces the addresses including the post code. This will allow engineering companies to upload their letter and mail merge their data. Ideally this needs to work for UK and Ireland.