Channel number display timeout?

Hi. been browing the forums for a few weeks now and been able to fix any little niggles i had to get my box installed but one last thing I cannot find for the life of me is an option to change the time the channel numbers are displayed for before disappearing. for instance my missus is blind but by the time she finds the second number key to change the channel the first one has already disappeared. ive tried changing all the timeouts but no avail. We are using the openatv 4.2 image and tried the default skin the bluev3skin and are using metrix hd as its great.
We came from a skybox which had very few options at all but did have a channel number timeout function to these which has almost every option imaginable but just not this one. I figure it could possibly be changed manually via a file in the skin somewhere but cant for the life of me find the right place so was wondering if anyone here could point me in the right direction.