What did i do wrong with this irule for redirection based on url

Try this modification with some logging enabled and let us know what the results are.

This should log the incoming [HTTP::host] and [HTTP::uri] at the beginning of the iRule so that you know what it starts with. From there you should know if it qualifies for the first if statement.

The second is just prior to the [HTTP::uri] compare.

when HTTP_REQUEST {
log local0. "Incoming URL - HOST:[HTTP::host] URI:[HTTP::uri] 
 Check if the request is for the root document
if {[HTTP::path] eq "/" } {
switch [string tolower [HTTP::host]] {
"devsmk.landrover.ourwebsite.com" { HTTP::uri "/landrover/vin.aspx" }
"devsmk.jaguar.ourwebsit.com" { HTTP::uri "/jag/vin.aspx" }
}
}
switch -glob [ string tolower [HTTP::uri]] {
log local0. "URI Compare - URI:[HTTP::uri]"
"/jag*" { pool pool.containing.jag.files }
}
}