Glowworm Complheat 80 Fan Problem

Can anyone help with this problem please? I need to remove the flue fan from my Glowworm Complheat 80 Fuelsaver boiler. I undid the two screws as per the manual, but it won't budge, being stuck at the top where it meets the flue. What holds it there? Is there a clamp, or do I just use brute force?
Any help much appreciated,
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