The mainstream position of Orthodox Rabbanim in the UK has consistently been not to attend Limmud, or any other pluralistic platform that undermines the foundational tenets of Orthodoxy.
When Rabbi Mirvis took the step to change that status quo, the move was met by uncharacteristically strong criticism from the leaders of UK's Orthodox communities. A strongly worded letter was published by seven of UK's most senior Rabbis - including Rabbi Avraham Gurwicz, Rosh Yeshiva of Gateshead; Dayan Chanoch Ehrentreu, head of London Beth Din; Rabbi SF Zimmerman, Chief Rabbi of Gateshead - denouncing the involvement or presence of any Orthodox Jew with Limmud.
This article quotes Rabbi SF Zimmerman, then Chief Rabbi of Gateshead [now leader of London's Federation of Synagogues]:
Rabbi Zimmerman said the statement reflected “the commonly held
principles of every Torah scholar in this country”.
In an article published by Jewish Tribune, Rabbi Zimmerman explained the fierce opposition held by Orthodox Rabbinate (quotation from here):
"Torah Judaism isn’t a product that can be sold one amongst others as
on a supermarket shelf. The idea of pluralism and the idea of Limmud
has been to establish Orthodoxy as one of many choices.
“In that idea there is a Judaism which believes in a Divine Torah.
There is a Judaism that believes that belives that the written law is
Divine and the oral law isn’t. Then there is a Judaism where neither
Torah nor G-d exists and these are all equal ideas and one is free to
pick and choose what’s best for him.
“In fact, the roll call of lectures at the Limmud programme seems to
include it like a list of phone options. For Authentic Torah press
one. For Written Torah that is Divine but not oral law, press two. For
written and oral Torah that’s not Divine press option three. For
pro-Palestinian demonstrations press four, and if you want to dance at
a disco party in your pyjamas press option five.
“By treating Torah as such they are debasing Torah, not promoting it.”
Some argue that if Orthodox rabbis went, they would be able to reach
out to those “at the far end of Orthodoxy.” But that was a fallacy, he
contended: Outreach could only work in an environment where one didn’t
“belittle” Torah.
“In an arena where Torah is defamed,” he said, “where it is equated to
non-belief, then the spark of Torah won’t be able to light up
anything. I’ve met many people who became religious as a result of
attending a Torah seminar. There aren’t many reports of people who
came back from Limmud with a determination to became more religious,
to commit to practising more.”