"I'm wondering why Scotland has so much public money spent on it by the UK government"

Again spending throughout the UK is not primarily based on per head of population. It is based on the cost of providing services. There are a whole range of factors which affect the said cost. This is how it works throughout the UK including within England itself. By the UK govt's own criteria Scottish spending should be higher than spending in England because of the said range of factors. Actual spending is even higher than it should be but still doesn't amount to a subsidy as Scotland over the years has paid its way. The lastest figures did show a deficit but again it is better than the deficit for the rest of the UK. The point being that if the official figures are all to be believed then the rest of the UK would be in a worse financial position without Scotland.

The whole discussion going down this route is fruitless anyway. Scots who want independence don't want their taxes going through Westminster prior to coming back to Scotland. Likewise the most popular option in Scotland is for devomax which is basically moving towards fiscal autonomy within the UK. That is money being raised in and spent in Scotland with Scotland then paying the UK directly for things like defence etc. Ardent unionists or anti-devolutionists should be asked to defend the present financial system - not people who want to see an end to it!