How to read the charts

The chart shows the best frequency to use if working from the UK to each area. The dark green (squares) plot shows the optimum frequency and the light green plot shows the next best frequency to use. The dark green blob plot shows the reliability of the path as a percentage that it is likely to be open.These are based on CW, 100W, dipole to dipole and a "fair" reception. Adjust the reliability according to your own station.

For more general charts see http://www.infotechcomms.net/propcharts/

United Kingdom

Reliability/Band graph produced by WinCap Wizard/VOACAP
This shows that to work the UK-based stations from within the UK, 80m (3.5 MHz)
is probably your best bet. However, as D layer absorption builds up during morning you may find signal levels dropping off.
40m (7MHz) will then be the band of choice if the critical frequency gets high enough. If that doesn't work for you revert to 80m.

If you are closer than about 100 miles you may even find that you can work the station on 20m, especially on CW.