Which big, strong alu frameset?

I’ll get the vital stats out of the way first. I’m 6’4″ and 117kg (and losing weight. I was 127kg a few weeks ago).

Anyway. I’ve been riding my Trek 1.5 (58cm) for the last 3 years and it’s developed a tremendously annoying creak. Eventual diagnosis is that the frame is actually too small for me and 3 years of putting so much leverage through the seat post has caused it to wear the inside of the seat tube where it now creaks with any shift of weigh in the saddle (pedalling, riding over gravel, etc.)

So I’m looking for a new frame. An upgrade. I don’t want a whole new bike as I’d just bought a 105 group set for the Trek, so I’d like to take that with me.

I’m looking for something strong and fairly stiff (as my size/weight/powar! do seem to cause stresses on the bike) and that comes in a 60-61cm size. I have a max budget of £800 but if it comes in under that The Wife will be happier.

I’d initially fallen in love with a 2011 Cervelo S1 Soloist but when I called to buy it was sold out, and it’s a discontinued frame.

I’ve been advised against certain brands by my LBS, but I can’t say how financially skewed his motives may have been, which is fair enough.

So, your recommendations please for a good looking, ~60cm frameset that’s reputedly pretty strong.