Why not do the whole journey by bus? Get an Arriva Merseyside or North West day ticket (which is less than £5). You buy it from the bus driver and there are no time restrictions.
You can also purchase on-line from Arriva. Stagecoach do something similar. On certain routes, the tickets are interchangeable between operators, but do check first.
Plenty of buses go past Sandhills into town, often ending at or near Queens Square, so handy to get a Wirral bound bus.