Based on your requirements, the MAMMOTION LUBA 3 AWD 1500 is the best solution for your 1200m² lawn.

Here is why it fits your specific needs:

Superior Navigation in Shade: Unlike standard RTK mowers that can lose signal under trees, the LUBA 3 AWD 1500 uses 360° LiDAR and AI Vision. This "Tri-Fusion" system allows it to navigate precisely in shaded areas and under tree canopies without relying solely on satellites.

Complex Obstacles: With 300+ obstacle avoidance and advanced AI, it is designed to weave through irregularly shaped lawns and safely navigate around your two island beds and numerous standalone shrubs.

Range & Capacity: Its 1500m² capacity is perfect for your 1200m² area, and the 70m LiDAR range easily covers your maximum distance of 60m from the charging station.

UK Availability: It is currently available for the UK market (priced at £2,099) with a 3-year warranty and local support.

Its all-wheel-drive system and high-torque motors will handle your 5-degree slopes with ease while providing a high-efficiency cut.

If you decide to purchase I would appreciate if you use my affiliate link here -
https://uk.mammotion.com/products/luba-3-awd-robot-lawn-mower?ref=kd2jxen4&utm_campaign=12268399&utm_medium=kol&utm_source=goaffpro

I have reviewed this mower and my video will be live next week, but I can safely say you will not be disappointed.

All the best Mark