Migration from 3.7 to 5

Hi

I am trying to migrate a site from Sitefinity 3.7 SP4 up to v5 but am experiencing various issues as follows:

I've followed the migration guide but when I attempt to use the migration tool it returns a 404 from the URL provide, if I access the URL in my browser it works fine and I get the following message from MigrationService.svc:

"ErrorMessage":"Authentication failed.","StatusCode":"403","Status":"Forbidden","Data":""

So the migration service appears to be working as documented. I've tried this on both http://localhost an1d also http://localdomain where localdomain is added to the hosts file and resolves to 127.0.0.1.

My other issue - I've copied my existing files into my new v5 project and attempted to build it - I get loads of errors from my existing user controls (we have around 100 user controls).

It appears that Telerik.Cms namespace is no longer used in v5, can you tell me the v5 equivalent? I have an awful feeling that I am going to need to rewrite all our controls which potentially means it may make sense to look at alternative CMS given that we would be pretty much starting from scratch.

Thanks in advance