Under review means that plans for superfast broadband in this area are not yet confirmed. The project target is to secure solutions between now and the end of 2019. Areas under review are still very much part of the SFSY programme, although are under review due to the technical challenges and/or costs at this time. As technology advances costs reduce and it is anticipated that solutions will become available to these areas.
You may wish to consider exploring alternative options to purchase a service such as satellite, wireless or 3G/4G mobile solutions. There are a number of companies who provide such products and these can be found through a simple internet search; examples of such local suppliers can be found below:
Wireless: IDAQ, KAT communications, One2Call.net, ITS Technology Group, Bliss Internet Ltd
Satellite: Satellite Broadband Guide
3G/4G: Mobile Wi-Fi (Mi-Fi) Comparison Guide
Alternative solutions
If your area isn't currently included in the Superfast South Yorkshire Programme there are a number of alternatives that can significantly improve your current speed or provide a connection while you wait.