Sorry, Simonj, that you haven't gotten a response yet
In the meantime, you might want to search this forum by searching on 'wifi problems'. You will will find ideas such as
Router settings--password protected? Change to a different channel from what your neighbor is using?
Os iPad version?
Does your iPad work in another setting? If it does go there and check that wifi statistics from your iPad and figure out the difference when you return home.
To, have you rebooted your iPad recently? (not just put it into sleep mode)