Different coloured roses on same plant

i planted a new climbing rose a few weeks ago and it has just started to flower with one beautiful deep red bloom.  Then a second bloom appeared which was an entirely different colour - deep pink but distinctly different.  Does anyone have any experience of this and, if so, is it likely that it is a one off or something that will repeat?  Can't remember the name of the Rose but it's David Austin.  Can look it up if important.