Welcome back to archery!
I don't think the turnover of archery equipment works quite the same way as other sports. Just from what I've seen here and elsewhere on the web, big manufacturers like Hoyt or Win & Win release new products with their new catalog at the start of the calendar year (and you'll see plenty of excitement on this forum when they do
). Most products seem to be around for a few years before they're replaced by newer models; every once in a while a good product is discontinued, and some distributors will offer the last of their stock at a discount - the Hoyt Matrix handle last year was a good example, as were Hoyt Vector limbs a while back (you can still find these some places). It's usually not a huge savings, maybe £50-100 total off your £500 bill...
You'd probably save a lot more by buying used equipment.
Whether you buy new or used, if you're returning to archery (i.e. already know what you're doing), and you don't have the budget to upgrade equipment as you go, then you won't want to bother with an entry-level handle or sight. For limbs: as worthipa pointed out, KAP Challenger are good value if you're building up technique and changing draw weight, but once your draw weight is where you want it, you'll definitely want a better pair of limbs. Maybe you could find a dealer with a trade-in policy, or who has used equipment in stock? Good luck!