Why is Meantime draft lager so bad?

Schonramer - as it arrived

Meantime is a Greenwich-based brewery that has two pubs in the area. I've been to both a few times, and I really want to like them, but I just don't.
Actually it's not the places themselves - the Greenwich Union on Royal Hill, and the Old Brewery at the Old Naval College - because they're both smart. Really nicely done out and the Union, which for me used to have a bit of a pong about it, is a really nice pub.
It's the draft beer I don't like. Maybe I'm doomed to suffer because I don't like ale and stout and all those drinks that beer bores slurp down. I like lager.
I went to Bruges recently and one of the things that sticks out is how much better the beer is there - all kinds of beer.
They take it seriously, and the people at Meantime clearly take it seriously too, but their lagers - and variants thereof that I've tasted - are hopeless. At best, not bad-ish and at worse, really, really awful. And expensive.
When I was in one of their gaffs the other day I started with a pint of Schonramer (£4.35, I know) and it was alright. Mrs Biff had a Meantime Helles, which in her words tasted 'like water'. I had a sip to confirm. So far so ho hum.

Five fucking quid

Next up we went for broke with a trappist beer cos we're mad like that. Westmalle to be precise and it was ace - 9.5% and a cool five pounds a bottle (I assumed the glass was a prezzie). It seemed to work at an accelerated rate as I had a monster headache two hours later. 
The grub is ace at the Union by the way, although it's not cheap at £11.30 for a burger and chips. But back to the beer, lastly I had a London Lager, a Meantime-brewed beer. I'd had this before and didn't think much but I gave it another bash.
This was the worst of the lot. It tasted like a bad Kronenbourg - no life at all. That seems to be a trend with the Meantime lagers, they're dead flat and have that sort of bad-Stella taste to them.
These places are charging top dollar for what is, in my opinion, mediocre at best lager. You can get a good drink there, and the Westmalle was spot on, but why should we have to pay a fiver (!) to get a nice beer? It's insane. I don't want much and I don't claim to be a beer expert, I just want want the Belgians get. And that's not a phrase you hear often.

London lager

For the prices they're charging (Meantime, not Belgium) - and getting, these places are busy - I can go elsewhere and get a crap lager for cheaper.
And I don't want to do that. I want to support places like this, and I don't mind paying for good stuff, but I always feel like I've been mugged after a visit to either of Meantime's gaffs.
These pretzels are making me thirsty.