Firstly, (and I'm sorry to spoil your elite party), if you paid £4k for an IMC rating you've been well and truly bent over and buggered. Providing you can make the grade in decent hours, £2k is more like it.
Don't underestimate the usefulness of an IMC rating, especially if you're hour-building in the UK and don't want to be grounded when it's hazy or there's low cloud around. Some regard it as a "get out of jail" card, but the DH minima are just the same as those for an IR (contrary to what some would have you believe). I've taken off in 2000m viz, cruised above cloud in the sunshine at FL100, then flown precision approaches to <300ft on my IMC rating. It does not give you access to Class A airspace, and has a 1800m viz limit for take-off/landing, but aside from that, and within the UK, it confers essentially the same privileges as an IR. You'll find it has a huge effect on your ability to hold headings and altitudes far more accurately without evening thinking about it.
As far as wasting money goes, it's entirely possible to do your PPL, Night Qual, IMC Rating, Hour Build and CPL, and still not have 200hrs in your logbook. I had my 100hrs P1 before I had my 150hrs TT and I did the IMC rating. Don't knock it until you've tried it!