How does T212 fulfil market orders?

So I just put a market order for BTG (LSE) 120 shares and it's been pending for 10 minutes!

I have an account with Scottish Widows (was iweb) for a long time, and I put a market order there and it fulfilled immediately.

This reminds me of that one time that you couldn't buy GameStop through most of these apps but my iweb/scottish widdows account would buy and sell orders just fine.

Anyway, has anyone else noticed this problem before with any particular stocks? I put market orders through other LSE stock and NYSE and it was fulfilled immediately just now.