I’m of the opinion that single small telescope, weather limited transit searches such as those that can be run from the UK will struggle to make headway. In part this is because the large scale survey projects, especially space based ones like TESS, are quickly hoovering up all the low hanging fruit that is likely detectable with amateur equipment but also because there are already so many transiting Exoplanets now that the professional observatories have a hard time following them up and undertaking long term monitoring, creating an ideal niche for amateurs to fill. There is a lot of good science to be had from observations of already known systems.
All that said, there are many viable alternative approaches for getting involved in new Exoplanet discoveries, all of which stand the best chance when working as part of a widely (global) dispersed pro-am team. The first is candidate winnowing where you increase your chance of success by observing targets already suspected to host transiting Exoplanets. Another is by observing known transiting systems on the basis that if there is one transiting planet already then you know the system is preferentially aligned, increasing the chance of discovering additional planets. A third approach is via transit timing variations (TTV’s) when the transit times are measured precisely enough to detect the effect of (unseen) companions as they interact gravitationally with the transiting planet. This is one of the most powerful techniques in Exoplanet observing, used extensively in the Kepler data set and which has already led to discoveries from small telescope observations e.g. https://arxiv.org/abs/1806.03503. There is one final approach which is to undertake searches using publicly available survey data, which doesn’t even require a telescope.
I guess what I’m trying to say is that there’s many ways to get involved in one of the fastest moving and most exciting areas of astronomy (in my unashamedly biased view).