Are there any of the cheaper ones that are any good that will fit a 56 lower cup? I’ve looked at a fair few and none of them seem to out of the box.
I know you can use threaded bar and washers etc, but that’s still a bit of a fiddle trying to get the cups in straight, so I’d prefer a ‘proper’ one with stepped mandrels to at least try and keep the cups centralised.
CRC would be good as I’ve got vouchers…

Would it be worth taking to a lbs as it’s a bit of a one off job?

I use the bolt/ huge washer tool myself. A bit scary but it does the job if you just take it really slow and check alignment as you go.

Hammer and block of wood.

I go for the frame on my shoulder & 2 flat bits of steel & a vice

I’ve previously used all of the above, but I’m currently switching headsets a fair bit, so I’d like the actual proper tool for the job to minimize risk of damage.