Hi ,the easiest way to get the giffgaff Internet on your phone is by sending a text with the message “SETTINGS” to 2020 ,if you use this service please re-check your settings afterwards for one wrong entry (please check & edit the browser Proxy IP address to Blank if there )
but if that doesn't work for your phone then you could try the following
As your phone is an android based phone you maybe able to use an app from the play store to install the giffgaff APN settings ,see the link below
Or you could install an android giffgaff app
If that doesn't work on your phone then
you could look to see the internet settings for most androids here and add them manually to your phone
Go to Settings.
Choose More Settings.
Choose Mobile networks.
Choose Access Point Names.
Press the Menu button on your phone and choose New APN.
Tap Name and type giffgaff, then tap OK.
Tap APN and type giffgaff.com then tap OK.
Tap MMSC and type http://mmsc.mediamessaging.co.uk:8002
Tap MMS proxy and type 22.214.171.124
Tap MMS port and type 8080
Now press the Menu button on your phone again, and choose Save.
Tap the little circle to the right of the profile named giffgaff on the list. It should turn green.
Your phone is now set up for giffgaff's internet and MMS settings.