Julian Cope presents Head Heritage

One possibility of indicating modernity whilst staying in keeping with the general vibe would be to accompany the motif with a series of small cups and grooves, along the lines of:

011100100110111101100011011010110110000101110010011101000111010101101011

Which is the text 'rockartuk' expressed in binary. It's obviously a bit too long to wrap around the CnR motif, but might make a good line if wrapped further down the outcrop.