I have an email address that I use for work, I use Mozilla Thunderbird on my laptop for handling these emails. I have recently set up a gmail account and have set my work emails to also fwd there too, worked fine at first but in the last couple of days I have noticed that sometimes emails are sent to the gmail but not delivered to me at Thunderbird. This is quite important and needs to be fixed as I only really use the Gmail for checking emails on my BB when I am mobile and I need to get all of them at Thunderbird as the primary source.

This is a strange 1 .. when you say you forward the emails to Gmail, are we to presume that you have set a rule up in Thunderbird where all emails that come in are then forwarded to Gmail? If that is the case then they must arrive in the thundrbird account first before the rule can forward to Gmail so if you are not getting them in Thunderbird they must be in your spam folder, otherwise maybe you can tell us how you set the forwarding up.

Cheers

Is the work email also via gmail?

Also how did you setup the work email to forward to gmail?

Not exactly clear as to what you're trying to do. Is your work email a Gmail account also? And, why do you need to go to Gmail on the web to check your email. You know you can have multiple accounts on Thunderbird, don't you? Anyway, my advice is to use a portable Thunderbird and use it on any computer. Here's the link to check it out:

http://portableapps.com/apps/internet/thunderbird_portable