Hello! Thank you very much for your offer of assistance. I have done very little these past few months as I have been preoccupied with moving house, which I am still in the process of doing. Hopefully, I will be able to be more actively involved again when I am fully set up in my new home. However, in the meantime, your assistance is greatly appreciated.
However, the situation is somewhat complex. Are you familiar with Github? There are currently two branches for Pak128.Britain-Ex on Github; one that is similar to the current released pakset, with a few changes, and one which is based on the next version of the Simutrans-Experimental executable that has a very large number of changes, including half-height support. Half heights are not supported in the current version of the Simutrans-Experimental executable, which itself lags behind Standard (in large part because there is more available programmer time for Standard than Experimental). This latter version of the pakset is the one that is in active development, as, given my limited time (even when not moving house) compared to the extremely large list of things that need to be done, I thought it more efficient simply to work on the branch that is ready for the next version rather than have a very large amount of time repeatedly consumed by branch switching and merging that would be necessary were I to separate meticulously each feature that is and is not supported by the latest executable version and put them on separate branches. The result is that nearly all the recent changes, whether they depend on the latest executable or not, are in the half-heights branch on Github. That is the branch on which you will probably find it beneficial to work, although you will not be able to use this compiled version without also compiling from source the latest Simutrans-Experimental binaries from the "way-improvements" branch on Github of the executable.
One of the first things that it would be very helpful for you to do is to fix the graphical errors with the icons of some types of bridges caused, I think, by the icon field pointing to the tooltip rather than the icon graphic for the relevant type of bridge. Secondly, it would be very helpful to merge recent additions to the Standard version of the pakset present on Github, but one should be careful with this, as a number of new things either need extra data to work with Experimental, or are balanced differently in the Experimental version of the pakset and will need adjusting on merging (or, indeed, both). The prices/costs of most items are not fully balanced and will need rebalancing in depth at some point in the future (but this will be a gargantuan exercise only worth undertaking when numerous extra features in the code affecting balance and making the balancing process easier have been implemented), but other things such as vehicle power, for example, are sometimes balanced differently in Standard than Experimental (the latter tending to prefer realistic figures).
The best thing, I think, to do is for you to identify some things of the above descriptions that you think you can do, describe in this thread what you plan to do, and we can discuss what, if any, adjustments to things incorporated from Standard need to be made.
Apologies that this is a rather more convoluted response than you might have hoped, but in the circumstances that I describe, that is rather unavoidable; your offer to help really is very welcome, however, especially given that I have had little time of late to do much work on this myself. Do let me know if anything is unclear, and thank you again.