I always check the ferry price against EuroTunnel now.
And cos I'm bored

I've done it for you. Assuming you're on your own & going out at 8am on Fri and returning 6pm (or near as) on the Sun;
Eurotunnel
Long stay promotion, book at least 1 day in advance, change times at no fee, but no refund; £128.50
Long stay holiday, book at least 14 days in advance, chang etimes for £30, refund for £60 cost; £148.00
Long stay flexible, book at least 3 days in advance, change times at no fee, refund for no fee; £154.00
Ferrys
Hoverspeed:- Special offer ticket, no refunds or cancellation allowed; £133
SeaFrance:- Special Fare is amendable, however no refunds are allowed; £110
Even if it's £20 more I'd go Eurotunnel - no strapping the bike down, no ages loading the ferry (1 hour? compared to about 10 mins for Eurotunnel), no stairs to climb sweating with all your gear; Ride on, park the bike and stand by it chatting. 30 mins later ride off
At both ends you're literally straight on to the motorway if need be, no port to negotiate.
Eurotunnel trains also leave roughly every 15 mins, so if you book a flexible ticket you won't be waiting for ages should you miss it or turn up early.
Also, pillions effectively go for free with Eurotunnel - I assume ferries will charge.
Don't think I'd take a ferry again