Graeme,
I too can see that you are very loyal to the Gooners but on the whole Football Club investments don't seem to do well for the shareholders at least. I seem to remember a Unit Trust or some similar type of collective investment investing in football clubs, which was managed or offered by Alan Hansen back in the 90's, anyone know what happened to that.
I would place this type of investment among the riskiest and limit portfolio exposure to less than 5% (maybe even 2%), it has to be money you can afford to lose Graeme. I have been through all sorts of investments with risk scales from 1 thru 10 (most at the upper end of the scale) and made enough to jack in work, but now I wouldn't invest in something as risky as this as I think of capital preservation.
One more thing to consider, have you got enough cash tucked away to cover the unexpected costs of new boiler, roof repairs as well as your estimated wedding expenses that you may incur. Keep your options open because if you do need money back in a hurry, this could end up being like the Commercial Property Funds where investors have been locked in for the last 2 or 3 years and cannot access their cash. You always need a buyer for your shares and there may well be a wide spread in the buy / sell price.