Are they, all of them, most of the jobs you listed are self-employed jobs, are they all declaring their whole income, are they paying all the tax they should be, why would Muslims be so special.
I can't imagine for a minute that most jobs in business, medicine, politics or law are self-employed. My assumption is that "Muslims are productive members of society" means that they are no more or less productive than any other category of people - and that this was the point being made here.
If diversity is our strength then why are we in such a mess.
There are many reasons why we're "in such a mess", including an overreach of DEI. Divisiveness and tribalism can also cause a mess. But equally, there are lots of things that aren't in a mess. One thing I would call out though as an example of a mess, that has been mentioned by PPs above, is Sharia courts. Personally, I think allowing them is a massive DEI overreach. Although their decisions aren't legally binding, I can't imagine too many women come out with a fair deal in marriage/divorce disputes or choose to exercise their legal rights to override them (owing to community pressure to conform to the decisions).
If we need immigrants for the economy, why aren't we the richest nation, considering the millions of immigrants we have, why isn't our economy booming, why aren't we the envy of the world.
I would assume we need immigrants for the economy as much as any other nation does. Every country has to grapple with how much freedom of movement to give foreign citizens to live and work within it. And obviously not every Muslim is an immigrant. According to ONS figures (which I trust more than BBC Verify TBH), immigration in the UK is on a downward trend:
https://www.bbc.co.uk/news/articles/c70989jrdweo
Also according to the ONS, only 6.5% of the UK population is Muslim: https://www.ons.gov.uk/peoplepopulationandcommunity/culturalidentity/religion/bulletins/religionenglandandwales/census2021