Spare/space saver wheel Octavia MK4 estate

Hello. Bought my MK4 vrs last month and it came with the foam spray and air compressor which is obviously useless if you have a blow out. Rang Skoda the other day and they are quoting about £70 for the jack, tyre iron etc and another £220 for an 18 inch space saver with tyre. They've said it will fit my car which came with 19 inch wheels (I'm aware it's still a space saver and 50mph speed limit would still apply). I'm assuming if I order and pay for it through a Skoda dealer I could return it if it doesn't fit in the boot for any reason. I'm guessing I would have to take out existing polystyrene base pictured below?