How can I reduce this gaming PC build to around £1,000 without losing upgradeability?

The graphics card is probably the easiest place to save money. A lower-tier card, such as an RX 9060-class model or a good used card from the previous generation, could bring the total closer to budget. The trade-off is that you may need to replace it sooner if you want higher settings in future games.

A cheaper CPU such as the Ryzen 5 9600X could reduce the cost while keeping the AM5 platform and a good upgrade path. If the 9600X is not at least around £40 cheaper, a Ryzen 5 7600X would also be worth considering. The CPU and GPU can both be replaced later, provided the motherboard, power supply, and case remain suitable.

If future-proofing is your main priority, keeping the RX 9070 and saving the extra money now may be better than buying a weaker card and upgrading again in a year or two. On the other hand, a temporary GPU downgrade makes sense if reaching the £1,000 budget is more important than maximum performance today.

A non-modular power supply is often a little cheaper, although the modular MSI unit is a decent choice and makes cable management easier. You may also want to double-check the unusually high memory and SSD prices, since those components should generally cost much less and could provide savings without reducing gaming performance.

To keep similar-quality parts at a much lower price, look for reputable used components through local marketplaces or second-hand electronics stores. Used graphics cards and CPUs can offer the biggest savings, but check the condition, warranty, and return policy carefully.