here are the frame dimensions:
middle of the bb to top of the seat tube- 56.5cm
top tube (middle of the hset tube to middle of the seat tube)- 59.5cm
middle of hset tube to middle of the bb- 64.5cm
hope this will help but please let me know if you will require any further info
Has the merlini gone? If not, is it definitely a 54 or bigger?