As opposed to Reading, which is nowhere in close proximity to somewhere.
The only way of comparing previous years standards would be to use subjects which don't ostensibly change, like Maths. I certainly know of a few mischievous teachers who have given A level Maths papers from 20 years ago to the current crop, and discovered that the average mark fell broadly by about 20% when asked to take last years paper by way of comparison.
I think you also need to clarify a time period as well. A level papers have been getting noticably easier for at least a decade, so you need to understand the point of reference, as if you're comparing standards from say, 30 years ago then there will be a difference. If however you compare them from 5 years ago, the difference will be minimal, if indeed it exists at all.
Also in order to compare like for like, I don't see how you can do so without making a concession to the dominance that coursework now plays. I for one refuse to believe that well educated, well resourced, and ambitious parents are not in a position to give little Johnny more than just a leg up if it comes between a university place of choice, and somewhere like Coventry.
I know from my own experience (I went as a so-called mature student) and joined the first GCSE intake, and was moderately horrified how poor they were. They seemingly tried to make up for it by effort and graft, but ultimately many of them were being educated beyond their intelligence, and laudible though their application was, they just weren't that clever. I managed to get dispensation from my placement year, and thus joined the last O-level generation for my final year. The difference was palpable. It's difficult for me to qualify it empirically, but I'd estimate they were 15 - 20% brighter.
I personally felt this is when it started. The replacement of the O-level had a knock on effect, when suddenly a lot of GCSE victims were being catapulted into A levels that they wouldn't otherwise have been capable of. The answer was to dumb down the A level. My own impressions were that my own degree was no more testing than my A levels as a result of joining (or straddling as it turned out) the two generations.
I'm sure I told you about a student we had recently, who was studying at the so De-Montfort University (known locally as the Demon Fart in recognition of its output). Remember this is an under-graduate. We presented her with a blank map of Europe and Africa and asked her to fill in the countries. She got France, Italy, Portugal, Germnany, Holland and Belgium eventually having got them the wrong way round intially, I seem to recall she identified Norway as Sweden, but have got it right eventually, and then gave up. Despite the fact that Eastern European countries had been dominating the news, she was oblivious to them. The African map was even better. She correctly identified South Africa (there was a clue in the name) identified Egypt as Saudi Arabia, and then gave up.
Now you might say that's no test of intelligence, and you'd be right, but God streuth cry I'd have done better than that as a 9 year old, and it doesn't exactly point towards the development of a rounded and knowledgable individual. I think there's a world of difference between memorising short-term facts and allowing others to assist in your coursework, and being able to understand, and place a series of inter related issues, complete with evaluating them, and their implications against a relevant background context.
Personally, I've seen little evidence to suggest that the A-level hasn't got easier, but believe this started around 1985 - 1990. The best will always cope in which ever generation they were in, but there those in the grey areas