How to prevent my kitten going through the cat flap

I know this is a strange question. I did a search on google earlier regarding this topic and it kept returning results for teaching your kitten how to use the catflap.

My problem is the complete opposite. So, I can only assume that I have a very clever kitty :rolleyes:

O.k. let me set the scene. I live in the country in a small open plan cottage beside my stables which houses 9 horses. I have 2 rooms with doors on them the bedroom and the bathroom.

I also have two adult cats. The first is a male cat, mao, who i rescued as a kitten from the side of the motorway. He is now three and is the worlds greatest mouser/rabbit-er/phesant-er... the list goes on and on... but, in short, he mostly likes to be outside only coming in for whiskas in the mornings or, on the weekends when im around more, for a snooze on my lap.

The second cat, munchie, is a mostly indoor cat. having long hair, she absolutely hates getting mucky so only goes out to stretch her legs and do her business - tho i have caught her using the kittens litter tray recently. But, I should emphasize that she does like going out - but only into the yard wheres its nice clean and dry.

The new arrival, my troublesome kitten is very adventureous. And now im getting worried that curiosity might just kill this cat :eek:

So i need suggestions because only this week she has learned to use the catflap. We have her two months and she was between 8-12 weeks when we got her. That means she must be four or five months old now. She herself came from my neighbours farm but her sister got killed exploring their farm. We have grown so attached to her that I couldnt bare anything happening.

I need a solution that will allow my two adult cats to come and go as they please without allowing the kitten out through the catflap.

I know you can get the catflaps that are magnetised but i cant dare let my male cat, mao, wear one because he goes on hunting missions through the shrubs and undergrowth and i would be petrified that the collar would catch on something and then he would die from strangulation/starvation.

I currently have the catflap blocked with a wooden board but this is proving troublesome because:

1) the male cat is really strong and can move the wooden board (its wedged up against the catflap with a cavity block - so when i say strong, i mean REALLY strong).

2) my female cat doesnt get that the catflap is now blocked and spends - god knows how long each day - pawing it/bashing her head against it trying to get out... I am sure she thinks I am totally retarded because I still havent "fixed" this particular "maintainance issue" :mad: which she keeps bringing to my attention when I get home by mewing at the catflap and then looking at me.

If anyone has experienced this particular problem and come up with an adequate solution please please post a reply... im so worried about my kitten.