There's not really a lot to elaborate on, the UK's location is the key reason why the EU is not willing to grant a Canada style deal. Elaborated here, as a low number of tariffs, and high quotas. There's more in this article on BBC.
Almost all trade agreements include them to some degree, but the EU is demanding particularly strict rules because the UK is a major economy right on its doorstep - therefore a bigger potential competitor than a country like Canada.
Being right on the doorstep makes it cheap to ship products. Anything produced in Canada comes with extra shipping costs and time to get to the EU, therefore the EU can be more generous in its terms because local products will be cheaper and available more readily based on "just in time" manufacturing chains to its consumers. Conversely Britain is closer to large parts of Western Europe than countries on the Eastern borders. Ireland in particular is practically divided from Europe in terms of transportation mechanisms by the UK.
A second point that doesn't seem to get mentioned much is market saturation. This FT article talks about the growth in EU exports to Canada since the trade deal. Even with the geographical difficulties exports are up 11%.
Overall EU exports to Canada rose 11 per cent in 2018 from a year earlier, while imports from Canada rose 7 per cent. Canadian agricultural exports to the EU, however, fell 15 per cent.
The imbalance stems partly from stringent European standards banning antibiotics and growth enhancement technology, Canadian meat industry bodies and farmers told the Financial Times. Farmers must have their methods endorsed by EU-certified veterinarians, who are in short supply in the Canadian west.
There is no such market for growth in relation to the UK. Anyone intending to export to the UK is already doing so, and the dangers in diverging standards is that the UK lowers its standards meaning it will be able to import from wider areas, or produce local goods at a cheaper price. This doesn't factor in any increase in costs based on new tariffs or non-tariff barriers, even simply completing a bucket load of paperwork and queuing to get it checked at the UK border can trim margins that exporters rely on.
I can't really address your final point on Services. Indeed from everything I've read the UK Government seem shockingly complacent over the issue, assuming that London will remain the home of finance across the EU indefinitely no matter what deal is eventually struck. But here's the institute for government's outlook. It notes the lack of a solid position from the British executive.
What is the government’s position on financial services?
The government’s written ministerial statement, published on the 3 March 2019, outlines that the government wants a free trade agreement with the EU.
As part of that the deal, the statement suggests that there should be “enhanced provision” for equivalence findings. These are unlikely to cover the full spectrum of financial services activity