First the good news: Animated Adventures at World Museum Liverpool has been extended slightly and will now finish on Tuesday 28th August. Also, the Culture Company is organising a family festival on William Brown Street from 12 noon until 5pm on 26 and 27 August, as part of the Mathew Street Music Festival, so you could visit both over the bank holiday weekend.
The bad news is that because of the family festival William Brown Street will be closed from 6pm on Saturday 25 until 8pm on Monday 27 August. Also, because of the 800th birthday pageant which starts and finishes on William Brown Street, the road will also be closed on Tuesday 28th August, so if you were hoping to park there you will have to find an alternative. Check out the World Museum Liverpool visitor information page for alternatives. Obviously the same arrangement applies to the Walker Art Gallery.