registration plate light mash up

[DR-VAN-HELSING]

Hi There. I had a blown Bulb on one of the lights to the reg plate. I ordered the wrong length and had to reorder. When I tried to pull the other one out which was working I broke the glass and shorted the fuse. I put a new fuse in which in turn got my front and back fog lights working as well as the heater ( Strange !! ) the only problem now is that the reg plate lights do not work. I am due an MOT in may and want to get this sorted. I am afraid to spend the cash on new ( second hand lights yet ) as I don't know if the lights are broken or it is something else electrical. What are the large square fuse things in the middle of all the regular size fuses ? Can any one help ? or does anyone know of a good mechanic in the oxford shire area ?? Thanks for reading this.