Does my fan oven motor need replacing?

Hi

I have a Tricity Bendix BS621 fan oven.

For a little while the fan has been reluctant to get going. Sometimes it doesn’t start spinning at all until the oven heats up a bit but it had then been getting up to full speed.

I have noticed now however that it doesn’t seem to be getting up to full speed at all anymore and things are taking longer to cook.

I have taken the back panel (inside the oven) off and removed the fan to check that there was no obvious problem or build up of grease (not sure if this is possible but thought it could be the cause) and to my untrained eye everything looks ok.

Therefore I’m assuming that the motor is on its way out but just hasn’t completely failed yet.

Can anyone confirm from the above information that my thinking is correct and that I need to replace the fan/motor?

As it is a fairly old oven I don’t really want to pay out for an engineer to investigate if the relatively cheap option of buying the replacement motor kit and replacing it myself will solve the problem.

If you need any more information please let me know.

Thanks in advance for your help.

Rob