Evolution of logo for 30th year in business

We are in our 30th of business. We have a very simple logo and all works well however we’ve got some nice press schedulled and it would be fantastic to have a 30th year graphic / reference added to the logo to celebrate our years of service achievement and a nod to the milestone.

“Now celebrating our 30th year serving our clients” could be a caption with the logo but I’m open for a change and whatever would suit / fit. I see this as very much a two part process. Initially some ideas / examples to choose from and then directive for a final design. This job is for the first stage of the process - the ideas / first drafts.

The business focuses on industrial / large scale commercial installation and maintaince HVAC for some of the most high profile buildings in London. View our website to gain a better perspective https://contractenergymanagement.com/

Attached are some quick drafts that a work experience junior designer delivered for us but they're not really cutting it with the directors of the business.

Final designs in .ai or .eps file formats.