Hi @tom.winterton, thanks for your reply!
I haven’t been spying on IE 
it’s just that I would love to see Lombard loans available to retail investors in the UK and not only to high-net-worth individuals via private banks.
The main benefit is that investors could lend money without taking money out of an ISA or incurring capital gain/corporate tax in a general/business account.
What would you use the loans for?
Property
What Interest Rates would you expect?
Something similar to mortgages or margins rates, see IBKR’s interest calculator: Margin Rates and Financing | Interactive Brokers LLC
“typical Lombard loan interest rates to sit between 2% and 5%” taken from:
2-3% see: Lombard loans | Base rates | Lombard Odier
Should we partner with a Bank to do this?
Maybe partnering with a private bank with experience with this kind of loan initially and, in the long run, take it in-house to cut any middleman fees.
What % of your portfolio would you expect to be able to borrow?
I would expect a range between 50% to 80%, but it depends on the liquidity and risk profile of the ETFs we will be using as collateral.