Hi I hope someone can help me. I have a third party extension recently installed and when it is enabled the Linnworks automation inventory sync fails. With the error Call to a member function getId() on null

I have asked Linnworks to send me a log of the API and they gave me this, i have changed the site name and removed/changed some of the long numbers in case it reveals any keys

REQUEST

POST http://www.mywebsite.co.uk/index.php/api/v2_soap/ HTTP/1.1
User-Agent: Linnsystems
VsDebuggerCausalityData: uIDPo68QtFPs/eJpoVYAAAAA/J4O4SIRFL7vc2mEnU431ZAueBPVqzuWsUACQAA
Content-Type: text/xml; charset=utf-8
SOAPAction: ""
Host: www.mywebsite.co.uk
Content-Length: 628
Expect: 100-continue

<?xml version="1.0" encoding="utf-8"?><soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"><soap:Body><catalogProductUpdateRequestParam xmlns="urn:Magento"><sessionId xmlns="">ed6f9b178cf42ee0426690</sessionId><productId xmlns="">802</productId><productData xmlns=""><stock_data><qty>10</qty><is_in_stock>1</is_in_stock><manage_stock>1</manage_stock></stock_data></productData><store xmlns="" /><identifierType xmlns="">id</identifierType></catalogProductUpdateRequestParam></soap:Body></soap:Envelope>

RESPONSE

HTTP/1.1 500 Internal Server Error
Set-Cookie: PHPSESSID=28hh90bp49o7nj0; expires=Mon, 30-Jul-2018 16:56:59 GMT; Max-Age=7200; path=/; domain=mywebsite.co.uk
Expires: Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Pragma: no-cache
Content-Type: text/xml; charset=utf-8
Content-Length: 308
Date: Mon, 30 Jul 2018 14:58:23 GMT
Accept-Ranges: bytes
Server: LiteSpeed
Connection: Keep-Alive

<?xml version="1.0" encoding="UTF-8"?>
<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"><SOAP-ENV:Body><SOAP-ENV:Fault><faultcode>SOAP-ENV:Server</faultcode><faultstring>Call to a member function getId() on null</faultstring></SOAP-ENV:Fault></SOAP-ENV:Body></SOAP-ENV:Envelope>