I agree. I doubt that he planned to just show up unannounced at his relatives’ place. He would’ve been welcome to visit them (although not by missing school), but there doesn’t seem to be a precedent for Andrew making such visits.Sorry, I don't mean travel to another city as a teen, because it's no surprise he would do that, to see the city for his own reasons.
I meant would you have travelled cities with the plan of surprising a relative on their doorstep? As a teen, I would not have done that; I would have called them first before travelling all that way and just showing up.
If for some reason he had planned to do that, why keep it a secret? Why not leave a note considering his well-planned clandestine trip would be exposed the moment he arrived at the relatives’ home?
Otherwise, he would’ve had only a few hours available to him in London before he would’ve had to have gotten back on the train to make it home before he’d be reported missing. What could have been worth the pain he’d cause? Coming back home the next day to a distraught family and likely police? A rock show for a band he wasn’t known to have liked? I don’t see it. He was said to be a polite and conscientious kid, normally.