problem selecting reverse and first when engine is warm

Hi all, i have a 2002 Scenic 1.4 and i am having trouble selecting reverse and 1st gear when the car heats up. It's like i have no clearance after a while. I had the clutch replaced a few months ago and it started soon after. I replaced the clutch pedal last week because i felt movement from side to side, but no difference. It only applies to reverse and 1st gear.Its getting to the point that i'm having to ram it in to 1st gear, and reverse is just embarrassing!! I have no problem in all other gears. The wife drives it most of the time, but it's doing her head in, and mine listening to her complaining!!! Any ideas out there, please???

problem selecting reverse and first when engine is warm