You need to set the MMS Max Message Size to 307200 which is 300KB, you currently have it set around 2MB.
Also check you have the :8002 at the end of mediamessaging.co.uk
Need a sim order one here and get £5 free creditj.mp/freeggsim or j.mp/freemicrosim
yes i have credit
yes internet works fine
i have just tried it but it still did not work