Your £300 would be better spent getting a professional to shoot the villa for you.
I shoot commercial interiors and architecture and there is quite a bit to do, I wrote a brief thing on shooting interiors for another forum I'm on; amongst other things to consider are:
High dynamic range, from the darkest corners to the brightest lights is more than a dslr can manage to photograph in one frame
Mixed white balance. The designer will want the colours of the wallpaper, furniture, cushions etc to be spot on accurate. One room can have several different colour temperatures, the table light, the chandalier, the downlighters, natural ambient light, they'll all be a different colour temperature. Get it wrong and you'll have all sorts of colour casts going on, stuff won't be represented in the right colour.
Angles / perspective. To show a room off to its full potential the temptation is to shoot with a really really wide angle lens. Then you find none of the verticals in the shot are straight, walls are bending inwards, verticals aren't vertical any more etc.
Getting enough light onto the scene, have you got portable studio flash to light it up? If so how are you going to shape the light to do what you want it to do?
Reflections. You don't want to appear in shot, nor does your camera, or light source.
As such in my opinion you'd be better placed spending the money on a pro and letting him or her think about all these different aspects.