Is our brand too close to a registered trade mark?

Mr. Weinrieb has given you a good SIMPLE answer, which is all that can really be provided here. However, as he stated, it is important to have all of the facts considered and there area number of facts to consider in these likelihood of confusion situations. The 3 factors that Mr. Weinrieb mentioned are probably the most important and what will likely determine if the mark can be registered but there are actually over a dozen different factors that courts use to determine if there is infringement.
More importantly and practically speaking, if you have not yet used or invested much in this mark, you may want to avoid the costly risk of trying to coexist with this mark. If you have already been using the mark and have not encountered any problems while also considering the good and services distinguishable, then maybe pursuing a registration is worthwhile.
I'm not sure if when you say "initial searching," you mean by an attorney with a professional trademark search or on you own on the USPTO website or internet? You are strongly recommended to consult an attorney for a professional trademark search because, as you may be learning, comparing marks is not very straightforward and neither is finding marks that could be considered "similar." Consequently, you not only are advised to have a trademark attorney review the details of the specific situation which you described, but also to conduct a proper search to ensure that you have uncovered all possible risks associated with proceeding with your existing or proposed marks. To not consult with an attorney here to save money could end up costing you a great deal more down the road.

Alex Butterman is a trademark attorney with Staas& Halsey LLP (http://www.staasandhalsey.com), a Washington, D.C. IP boutique law firm. Alex is admitted to the bars of Washington, D.C., New York and New Jersey but, unless otherwise specified, the answer is intended to be general enough to apply to any U.S. state and based primarily upon his knowledge and experience with applicable federal laws.

The opinions expressed are those of the author and do not necessarily reflect the views of his firm, Avvo or other attorneys. This answer is for general information purposes only and is not intended to be and should not be taken as legal advice. No attorney-client relationship or obligations are established herein, although consulting an attorney to discuss your specific situation is strongly recommended. This is especially true of trademark law because TM law is so fact-specific and full of esoteric nuances and exceptions that could easily result in a critical legal error without proper advice from experienced trademark counsel.

Without knowing the actual marks in question, it is difficult to render an opinion, however, there are three basic principles involved - all three are based upon the likelihood of confusion (of the source of the mark) - the first is how close are the marks in reality, the second is what are the fields in which the marks are used - you already indicated such - and the third is the strength of the mark that you might infringe. For example, if the mark is XEROX or GOOGLE, those are extremely strong marks and whatever fields the goods or services are in, there would be an immediate association with the original XEROX and GOOGLE companies. If the marks are not that strong, meaning very well/universally known, and the fields of commerce are different, then you are in a stronger position for not infringing the mark, however, again, it is difficult to truly say without knowing the actual marks.

I suggest you order the free trademark search from http://freeTMsearch.com

It's not just an automated search through an online database, you get real people, trademark agents and attorneys, do the search for you and walk you through the registrability report. For free.