Hiding tag and category root in wordrpess = plunge rank

[bizint]

I deleted the "tag" portion of my tag urls's that were ranking pretty high....so:

www.businessinteriors.co.uk/tag/office-fit-out-bristol became

www.businessinteriors.co.uk/office fit-out-bristol

The old tag page ranked 7 before the change and even 3rd at one stage.

The new name page without the tag has re-appeared at 23....

So quite a plunge in ranking from the change and this is across the board for all my tags (200) that were ranking high and I wanted to improve.

Have I made a major error? Or will they naturally start coming back to where they were before?

Weirdly  some of the changes have had a positive impact - so ranking has gone up slightly in some areas..but completely out done by the plungers :-s

[firstconversion]

Did you 301 the old urls to the new? Otherwise you would have all your incoming links pointing at pages that are 404ing

[bizint]

yes...the wordpress plugin I used took care of that....