How to extract data from XML/SOAP in Python

The UK National Gas system publishes a mass of data that can be access from a SOAP server and an example of the returned data (for LNG) is shown below. I've written the code to generate the request and to handle the response but am tripping up on how to extract the returned information. The aim would be to upload the data into a backend database or into a Pandas dataframe.

In previous code, I've simply traversed the XML using XPATH and then iterated over the tag and extracted out the child data. Thus, I was hoping to extract:

GetPublicationDataWMResult, ApplicableAt, ApplicableFor, Value, ...
LNG Stock Level,2016-03-13T15:00:07Z, 2016-03-12T00:00:00Z, 7050.42286, ...
LNG Capacity,2016-03-13T15:00:07Z, 2016-03-12T00:00:00Z, 6515042480, ...

Having tried to use XPATH to traverse the children (/Envelope/Body/GetPublicationDataWMResponse/GetPublicationDataWMResult/) it is failing.

The logic works if I sanitize the code by adding a series of string removals but that's sub-optimal and bound to break in the future.

EXAMPLE CODE:

import requests
from lxml import objectify

def getXML():

    toDate = "2016-03-12"
    fromDate = "2016-03-12"
    dateType = "gasday"

    url="http://marketinformation.natgrid.co.uk/MIPIws-public/public/publicwebservice.asmx"
    headers = {'content-type': 'application/soap+xml; charset=utf-8'}

    body ="""<soap12:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap12="http://www.w3.org/2003/05/soap-envelope">
        <soap12:Body>
            <GetPublicationDataWM xmlns="http://www.NationalGrid.com/MIPI/">
                <reqObject>
                    <LatestFlag>Y</LatestFlag>
                    <ApplicableForFlag>Y</ApplicableForFlag>
                    <ToDate>%s</ToDate>
                    <FromDate>%s</FromDate>
                    <DateType>%s</DateType>
                    <PublicationObjectNameList>
                        <string>LNG Stock Level</string>
                        <string>LNG, Daily Aggregated Available Capacity, D+1</string>
                    </PublicationObjectNameList>
                </reqObject>
            </GetPublicationDataWM>
        </soap12:Body>
    </soap12:Envelope>""" % (toDate, fromDate,dateType)


    response = requests.post(url,data=body,headers=headers)

    return response.content

root = objectify.fromstring(getXML())

Returned XML:

<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope
    xmlns:soap="http://www.w3.org/2003/05/soap-envelope"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:xsd="http://www.w3.org/2001/XMLSchema">
    <soap:Body>
        <GetPublicationDataWMResponse
            xmlns="http://www.NationalGrid.com/MIPI/">
            <GetPublicationDataWMResult>
                <CLSMIPIPublicationObjectBE>
                    <PublicationObjectName>LNG Stock Level</PublicationObjectName>
                    <PublicationObjectData>
                        <CLSPublicationObjectDataBE>
                            <ApplicableAt>2016-03-13T15:00:07Z</ApplicableAt>
                            <ApplicableFor>2016-03-12T00:00:00Z</ApplicableFor>
                            <Value>7050.42286</Value>
                            <GeneratedTimeStamp>2016-03-13T15:56:00Z</GeneratedTimeStamp>
                            <QualityIndicator></QualityIndicator>
                            <Substituted>N</Substituted>
                            <CreatedDate>2016-03-13T15:56:28Z</CreatedDate>
                        </CLSPublicationObjectDataBE>
                    </PublicationObjectData>
                </CLSMIPIPublicationObjectBE>
                <CLSMIPIPublicationObjectBE>
                    <PublicationObjectName>LNG Capacity</PublicationObjectName>
                    <PublicationObjectData>
                        <CLSPublicationObjectDataBE>
                            <ApplicableAt>2016-03-12T15:30:00Z</ApplicableAt>
                            <ApplicableFor>2016-03-12T00:00:00Z</ApplicableFor>
                            <Value>6515042480</Value>
                            <GeneratedTimeStamp>2016-03-12T16:00:00Z</GeneratedTimeStamp>
                            <QualityIndicator></QualityIndicator>
                            <Substituted>N</Substituted>
                            <CreatedDate>2016-03-12T16:00:20Z</CreatedDate>
                        </CLSPublicationObjectDataBE>
                    </PublicationObjectData>
                </CLSMIPIPublicationObjectBE>
            </GetPublicationDataWMResult>
        </GetPublicationDataWMResponse>
    </soap:Body>
</soap:Envelope>