Hotpoint Hvl 241 (Uk) - 2 And 4 Lights On - Suspect Pump Blockage

Hi

New to this so please be kind.

I have the above washing machine about 5 years old (maybe just past the parts guarantee - but hotpoint couldnt tell me if it was even though Im sure I registered).

It goes through a wash cycle but stops with the door light flashing quickly and lights 2 and 4 (top to bottom) flashing. There is water in the drum but I can open the door without it all spilling out. I have tried the program which just empties the drum but the level doesn't drop even though the pump seems to be running. Previously I removed and cleaned out the filter which was pretty well bunged up with crud but no objects (coins hairgrips etc). I am thinking that the pump might be bunged up. the waste pipe is clear but when I blow into the waste pipe, there is complete resistance. I would have expected a little less and be able to at least blow some air through the machine. Is my method so far a reasonable one?

Would others agree that it sounds like a pump problem

I aim to take a look further at the pump and filter but its at such a low level that its difficult to work on. can I turn the machine on its side without problems or even upside down if I need a new pump or will I damage it working on it in that way (obviously I would not start it in the non standard position).

Thanks for reading - hope someone can help