Low and short, Nellie and already starts later even without the hour difference.
Low - The angle of the sun in the sky affects the amount of sunlight that reaches a given area of the earth, In the winter, whereas the edge of the atmosphere in Penzance receives about 8 MJ/m2 of radiation , it decreases to about 2 in Shetland. Also the distance the sunlight then has to travel through the atmosphere affects how much of it is dissipated en route - particularly where there is higher cloud cover, as is the case in the west and north.
Short - The day is shorter at both ends as you go further north. If you are at 50°N, say in southern Cornwall, you go from about 8 hours day length in the middle of winter up to about 16 in the middle of summer. If you are in Shetland, which is about 60°N, the daylength ranges from about 3 hours in the middle of winter up to about 21 hours in the middle of summer. So for every degree further north you live, you lose about half an hour of daylight. in the winter. Unfortunately the extra summer daylight can't be frozen and defrosted for use in the winter.
Starts later - The sun rises later (and sets later) as you go further west (Edinburgh is as far west as Cardiff, Glasgow as far west as Swansea, and half of Scotland is to the west of Glasgow.) This can be more than an hour of difference.
There is a map of the latitude and longitude of the UK with principal cities marked at www.mapsofworld.com/lat_long/united-kingdom-lat-long.html and a transcript of a talk (quite long and detailed) on day length and latitude at www.google.co.uk/search?q=day+length+and+latitude+UK&ie=utf-8&oe=utf-8&client=firefox-b&gfe_rd=cr&dcr=0&ei=lq31WdC_KY7Z8AfHzqvwBA
Sorry this post is rather long and didactic, but I don't think I can shorten it.