My hosting account has a file limit so, to reduce files I don't bother uploading the licence file. Is this breaking the GPL License? I am not redistributing it without the license or anything just using the code.
No, it is not a violation of the GPL to remove any files (including the license file) before uploading. The GPL does not place any restriction on use or modification of a work, but rather only on redistribution of the work or distribution of a modified/derivative work.
In fact, the license states this scope explicitly:
Further, copying is only within the scope of the license when such modifications are distributed [emphasis and emphasis added]:
Note that "modify your copy or copies of the Program or any portion of it" is separated from "copy and distribute such modifications". The notice and license requirements apply only to distributed works.
The GPL doesn't compel you to do anything whatsoever with a work that you use and modify, but do not distribute.
Wordpress Codex officials wrote -
I think we can delete those files.