Hilton, for sure. It's closer. So is the Sheraton. Lowe's is downtown, not far, but Sheraton and Hilton have a hotel shuttle to the park and the Universal city walk.
I would not do Universal after the ABD though. Coming from the UK, you probably don't realize that LA is huge and the tour takes you to two far apart places. It starts in Hollywood and then goes to
Disneyland, so you will be at DL when it ends. That's about an hour from Hollywood, in Anaheim. So you'd be going backwards. It would be silly to do that. You'd also lose your post trip airport transfer.
Your best bet is Universal before. Either stay close to the park at Hilton or Sheraton and then move to Lowe's when the ABD starts (you'll lose your airport pickup, but you can taxi) or you can just go to Universal from Lowe's staying there a day or two early.
Check with Lowe's about transportation to the park first. I know from my last Universal trip that they have a Universal concierge but I stayed at the Hilton so I don't know what they have available.