tidy with new multicave wallets

templates/cavewallets.html

@@ -23,6 +23,8 @@ traced to produce Tunnel or Therion drawings and eventually the final complete c
 {% include 'wallet_table.html' %}
 <p>Note that names in italics are copied from the related survex file block name.
 <br />
+<p>Total underground survey length: {{length_ug|floatformat:"1g"}} m
+<br />
 <table width=95%>
 <tr><th>Wallet</th><th width=13%>Wallet Date</th><th>Wallet Name</th><th width=25%>People</th><th>Scans</th><th>Survex blocks</th><th>Drawings using these scans</th></tr>
 {% for wallet in manywallets|dictsort:"walletname" %}