The reason the change is urgent is that the transmission has been revving in gear and I was told based on a few family members experience with the same thing happening that this is usually remedied by changing the transmission filter and fluid.

Garage told me:
"There are actually 2 filters in these, one is an inline filter which is on the pipe connecting the gearbox to the gearbox oil cooler. This very rarely changed.

There is also another filter inside the gearbox but changing that filter requires gearbox removal and dis-assembly to change so not really a service item".

So what should I do...
Go for just fluid change?
or
fluid + first filter change?
or
fluid + second filter change?

Appreciate some opinions as it is urgent,

Thanks