Qualcast Electric Push Mower 1200w

Qualcast electric rotary mower, 1200 watt, 30 litre collection tray, 10 meter power cable, 3 height adjustment settings. Metal 32 cm blade. Model: GLM3300. We are selling this used mower we have had for 2 and a half years. Has been working fine from day one but we noticed it doesnt cut the grass as well as before. Not sure what the problem is and didnt seem worth getting repaired. Bought a new mower and selling this as  not working. Ideal for someone with same model or anyone that knows how to repair these.  99pence auction Collection only No returns accepted