hello Rob
As memory serves you shouldnt need to add length for a bent shaft. I think you'll have a hard time finding a shorter paddle than 184 but thats just as far as my memory (which is probably spotty at best) serves.
If I can tempt your fancy take a look at wavedog paddles
www.wavedogpaddles.com
www.wavedogpaddles.blogspot.com
they are super strong and light (especially for a wood paddle) I know that there have been some sent over to the UK and Europe. I paddle one and each paddle is custom made. They are unique, grassroots and the strongest paddle ion the market.
Oh yeah, they have an agent program starting up. not sure if in the UK but might be something to email about.
any specific questions feel free to email me... they gost got a top shelf review in paddler mag if that helps sway you too
take care and good luck on the search
oh btw... the collie is the smaller shaft of the 2