I had a chat with our village undertaker this afternoon (spotted him cleaning his car) and asked for his thoughts on this.
He said there are too many factors to be taken into consideration and he couldn't make a fair comment without knowing more about that particular undertaker's set up - for example, not all undertakers have their own chapel of rest and need to rent space in someone else's chapel when viewings are required (first I'd heard of that).
He also said there can be a lot of work/time involved in getting a body ready for viewing, some take much more time than others, and also the make-up used is not the sort you or I would have in our make-up bag - it is specially made for the deceased and is quite expensive.
Another consideration is how the undertaker pays his staff. I thought the chaps that collected the body were paid "per collection" with a small retainer perhaps, but not so with our local undertaker - he pays all his staff a salary.
Crematorium fees vary too. In my village the fee is just over £600, but further towards York, it's £700+. Burial is even more expensive.
He gave me a leaflet detailing a funeral plan - his charges were around £3,000 to £3,500.