Clio 197 F1 Gearbox 3rd & 4th crunch

Hi All

I know there is a lot of threads going regarding the same 3rd & 4th gearbox crunch, I also know it will need a rebuild of the gearbox as I have changed the gearbox oil and it didn't really make a difference.

My questions to you all,

1. Anywhere recommended in Surrey drive in and out?
what kinda cost for that?
Will they just replace with OEM parts and is it worth it?

Or

2. Would it be better to get the gearbox out and send to someone more knowledgeable with this issue?

Willing to buy a refurb gearbox also.

Any help would be appreciated

Thank you
Russell