I assume that the pink card reader at Whitechapel and Canada Water is essentially worthless with contactless for such journeys.
Just looked back and I bought an anytime day return between North Dulwich and Beaulieu Park for £25.80 at the end of October. This is also £34.90 now so a 35% increase!
Unfortunately this is one of the many journeys which are 'directionally priced' meaning the Anytime fare is significantly cheaper in the contra-peak direction. This made sense historically speaking but has generally been scrapped with the advent of single-leg pricing, since it isn't really possible to support directional pricing on TfL's PAYG system.
In most cases, the ratio between the Anytime and Off-Peak fare would mean that an Anytime Day Single on the way there, and an Off-Peak Day Single on the way back (generally no restrictions heading
into London in the evening peak), would add up to a similar amount as the previous directional Anytime Day Return fare. But in this case, the Anytime Day Return heading towards Beaulieu Park was so cheap (in fact cheaper than the Off-Peak Day Return!) that this has not happened.
This is exactly the kind of scenario that MPs should be lobbying the DfT about. Clearly you can't make an omelette without breaking some eggs, but the fare increases for journeys such as this are very significant and without any clear justification.