Zanussi Door Opens Whilst In Full Spin

Hello, i have had my Zanussi ZWF 1431W since December 2005, when the 1 yr manufacture warranty ran out i took out extra insurance via Legal and general, (paid monthly £700 in total) i have had no problems with this machine and have not had any cause to call for a engineer until last week my Grandson accidently found out the door could be opened whilst spinning, i contacted the insurance last Wednesday and a engineer came out today, he tested the machine and made a phone call i could hear the conversation, he was checking about a Technical bulletin with regards to this problem, he then replaced the door lock spun the machine at full spin and tried the door again and it opened, he made another call then cut the plug of my machine and told me Zanussi (stressing nothing to do with Legal and General ) was going to replace my machine, when i asked him about this problem he was very vague and just said not all models are affected but mine obviously was which is why they are replacing it.

I just wonder why as my machine came direct to me from Zanussi ( a replacement for the same model which had alot of problems)and it was registered with them why wasn't i contacted about this problem if they knew about this fault, Zanussi told me they have no knowledge of a problem but are exchanging my machine ??? my Grandson opened the door whilst it was spinning thank god i was next to him at the time (hes 4). Zanussi have offered me a replacement for my machine the machine ZWG 6141P costs about £225 it seems their cheapest machine, a lot cheaper than mine at the time i paid £389. same spec 6kg 1400 spin but lacking the digital display (which i quite like to see how longs left) i just wondered if anyone has had a problem like this, any advise please thanks Sue.