Caple TDi4001 Integrated Tumble Dryer Fan

Hi All

I’d like a bit of advice re: my Caple TDi4001 dryer. It’s 3 months old and up until last week it worked fine but now the fan is suddenly coming on and just staying on for the final hour of all drying cycles. The fan has always come on but only for a few seconds at a time for approximately 30 seconds over the cycle but never this long. I done several drying cycles and it is doing every time. Sometimes in a smaller dry it stop starts through the final hour but the stop is never anymore than 5 seconds before the fan kicks in again.
I contacted Caple because this was such a dramatic overnight change in fan running time but they have told me it’s normal and the TDi4001 is designed to have longer fan times compared to its predecessor so won’t send an engineer out under the warranty to check it. The problem I have is that I can’t let a local engineer look at it because it will void my 5yrs warranty so my hands are tied.
Is the fan running time normal when it’s on for over an hour in a 1hr 30mins cycle?

TIA