In the aftermath of recent trading volume levels that have just caught out AJB and seemingly Halifax and IWeb, I'm looking to move my SIPP holdings away from AJB - they've had good money from me over a few years but seemingly aren't providing a platform service level that I feel I can expect in today's day and age.

or "Shrug" in layman's terms. Its almost as if they just don't care - no direct messaging to keep me updated, no expectation of a 'when' it would be fixed.
It just doesn't feel at all professional for a company looking after vast amounts of people's pensions.
Can anyone recommend a SIPP broker that hasn't disappointed them in recent months?
(one that offers a full spectrum of UK shares, doesn't cost the earth per stock trade [I sometimes trade a number of times a week when I get too excited] and doesn't have extortionate platform fees)
I've been very happy with IG for ISA dealing, is there a close equivalent for SIPP holdings?