Hi
probably easiest to insert a new column to contain the first alpha characters of the code and use the following formula to extract. You can then use a regular countif:
<b>Excel 2007</b><table cellpadding="2.5px" rules="all" style=";background-color: #FFFFFF;border: 1px solid;border-collapse: collapse; border-color: #A6AAB6"><colgroup><col width="25px" style="background-color: #E0E0F0" /><col /><col /><col /><col /><col /></colgroup><thead><tr style=" background-color: #E0E0F0;text-align: center;color: #161120"><th></th><th>A</th><th>B</th><th>C</th><th>D</th><th>E</th></tr></thead><tbody><tr ><td style="color: #161120;text-align: center;">1</td><td style=";">Postcode</td><td style=";">First alpha</td><td style="text-align: right;;"></td><td style=";">Count</td><td style="text-align: right;;"></td></tr><tr ><td style="color: #161120;text-align: center;">2</td><td style=";">B15 6TY</td><td style=";">B</td><td style="text-align: right;;"></td><td style=";">B</td><td style="text-align: right;;">2</td></tr><tr ><td style="color: #161120;text-align: center;">3</td><td style=";">B4 9LP</td><td style=";">B</td><td style="text-align: right;;"></td><td style=";">BS</td><td style="text-align: right;;">1</td></tr><tr ><td style="color: #161120;text-align: center;">4</td><td style=";">BS12 8QW</td><td style=";">BS</td><td style="text-align: right;;"></td><td style="text-align: right;;"></td><td style="text-align: right;;"></td></tr></tbody></table><p style="width:3.6em;font-weight:bold;margin:0;padding:0.2em 0.6em 0.2em 0.5em;border: 1px solid #A6AAB6;border-top:none;text-align: center;background-color: #E0E0F0;color: #161120">Sheet3</p><br /><br /><table width="85%" cellpadding="2.5px" rules="all" style=";border: 2px solid black;border-collapse:collapse;padding: 0.4em;background-color: #FFFFFF" ><tr><td style="padding:6px" ><b>Worksheet Formulas</b><table cellpadding="2.5px" width="100%" rules="all" style="border: 1px solid;text-align:center;background-color: #FFFFFF;border-collapse: collapse; border-color: #A6AAB6"><thead><tr style=" background-color: #E0E0F0;color: #161120"><th width="10px">Cell</th><th style="text-align:left;padding-left:5px;">Formula</th></tr></thead><tbody><tr><th width="10px" style=" background-color: #E0E0F0;color: #161120">E2</th><td style="text-align:left">=COUNTIF(<font color="Blue">$B$2:$B$4,D2</font>)</td></tr><tr><th width="10px" style=" background-color: #E0E0F0;color: #161120">B2</th><td style="text-align:left">=LEFT(<font color="Blue">A2,MIN(<font color="Red">FIND(<font color="Green">{1,2,3,4,5,6,7,8,9,0},A2&1234567890</font>)</font>)-1</font>)</td></tr></tbody></table></td></tr></table><br />Formula in B2 is copied down