Its always better to be sure so better write a LoE.I will ring them up first thing today. If they were unable to rectify it having submitted already, then i'll write an LOE. Thanks a lot.
I suggest you to ask the clinic to e-mail High Commission regarding the error ASAP. It will take 2 minutes for them to do so. Meanwhile you attach a LoE explaining that how incorrect information was printed by the clinic inadvertently.
I had similar problem in my medical, the clinic made a typographical error, they had already submitted my medical. So the Dr. e-mailed the high commission regarding their error and immediately got a response back that the system had noted the error and will update.
The Dr. gave me printed copies of the content of the e-mail, stamped and signed them.
I attached those copies along with my LoE. I am still waiting for my medicals to be passed, So will know for sure that it worked when they get passes. But doing so, i feel that i explained to them in the best possible way. So hopefully it will be enough.