The other ....(3rd option) and more common response would be to buy a Good much newer/nearly new Bigger and Better model/spec'd used RIB...
£25k is a healthy used boat budget...but will be limiting going new.
You wont pay 20% Vat for a start and won't loose substantial amounts of money on resale value in the short term.
IMO a used potentially larger better spec'd PREMIUM brand RIB would be better to use...more enjoyable....more capable....and very probably hold value better
.....and without the Wait for the New model OR the considerable work/time off the water and stress of a complete Re-furb...when you'll have (in the end) the same (if a bit shinier) as you started with.
Why not try a few other Models/sizes it MAY be an eye opener.