First off, you'll have no problem selling it come the summer. Condition is everything and if it's presented right, with all receipts, work done, no reason you can't get £9k+ on a private sale. Engine does make a difference, so a mint Suzuki DF60 or DF70 is more desirable than a basic RYA safety boat with a single jockey with a Honda BF50 on the back. Genuine Ribcraft A-frame or internal fuel tank, that's a grand right there.
If you've only had it a couple of years, then you have a benchmark price to start from, plus the work you've invested in it, new trailer, etc.
Some examples here. Take the JBT price with a pinch of salt, but useful for an example of how it's been prepared.
2007 https://www.boatshop24.com/en/ribcra...latable/857166
2008 https://www.ribsforsale.com/boat-det...tboard-engine/
2016 https://rockmarineservices.co.uk/sb_...-broker.co.uk#