When mine got repaired, I noticed parts are not expensive. All those pipes, nuts, bolts, AHC parts n suspension arms from Toyota was 1600£. Those accumulators (round structures) don’t need replacement. It’s the labour Toyota told is expensive (40 hrs minimum). For independent mechanics as well it’s easy to replace AHC with normal suspension so difficult to find someone to do this job. I guess If AHC system is replaced once with new pipes n sensors, it ll go on for another 10 -20 years. Next time if it fails, I ll go for regular suspension. From the info I got from here n US site, it should cost around 2000£ for replacing AHC with regular one