viewing your source at:
index.shtml
the links look like this:
<li><a href="hotel-south-west-scotland.asp">GARDEN SUITE</a></li>
when at:
trigony-room-rates.shtml
the links look like:
<li><a href="<%=assumedRoot%>hotel-south-west-scotland.asp">GARDEN SUITE</a></li>
This bit:
<%=assumedRoot%>
is asp code that cannot be processed because the page is an shtml page. it would seem you have two different menus, one is a static menu, the other is an ASP menu. You will not be able to embed an asp menu into a static shtml page.