F05 is indeed a pump fault. Its nearly always a blocked pump that causes this.
But as to removing the filter if its full of water then it will flood out from there im afraid.
What you need to do if you can is pull the washer out and then get the waste hose and lower it into a bucket and gravity will drain the water out. Just lift the hose up to stop the flow of water.
Or another way is pull it out and lean it backwards against the worktop or wall and have some one hold it for you.
Then get a washing bowl and place it under the filter, You will also need a towel.
Then just slacken the filter and you can drain the water out from there.
Once all the water is out then you can fully remove the filter and clear it out.
Then look inside the chamber were the filter goes and there at the back you will see the pump impeller. Check theres nothing stuck in there as well.
But if you are not able to remove the filter then im afraid you need quite a few towels for this.
Then get a shallow tray under the filter and slacken it to drain the water out.
Now this way may take a while and it will leak more then the otherways.
So thats the only opitions you have here to get the water out. If you need anymore info just get back to me.