Even in the base case scenario on my back of the envelope calcs,...

Even in the base case scenario on my back of the envelope calcs, SHL is currently trading at a PE of 30. Not cheap for a low growth stock, however, looking at their performance over the previous decade it's clear that the business can sustain better margins. The CEO has been around a while (decades if I remember correctly) so I give credibility to management claims when they say margins will improve. There is also talk about how benefits from the recent acquisitions have not been realized yet (especially the AI aspect of this). My understanding is that because of the AI, margins can improve drastically, perhaps over what they were in FY20.
All in all at the current price I'm happy to hold a position. Depending on what mood the market is in, I think the SP could go below $28. I'd be very keen for a top up around $26 as that would mean the SP is trading at a PE of around 26 on a very conservative earnings estimate. I can't see it going any lower unless they made a mistake with their acquisitions and these are marked down in fair value.