How much does it cost to get axillary breast tissue removed in the UK from excision?

 You will find that the costs of surgery will differ from one geographic area to another, as well as from one practice to another.  You will also find that the cost of surgery vary  depending on exactly what procedure is recommended/performed.
 
You will be best off doing your due diligence carefully  in the selection of plastic surgeon.  Only in person consultation will provide you with the detailed information you should obtain prior to making any decisions about proceeding with surgery. Ask  to see lots of examples of their work and preferably speak/see patients who have had similar procedures performed. Learn about the potential risks/complications associated with the surgical options and ask about “realistic expectations”.
 You will likely find,  while doing your due diligence,  that there are many different “specialties” who will offer their services to you;   I strongly recommend you concentrate on surgeons certified by the appropriate Board of Plastic Surgery.  
I would also suggest that you do not base your selection of plastic surgeon primarily on costs of surgery;  keep in mind that revisionary surgery may be more costly in many ways.

I hope this, and the attached, helps.