I'm sure they'll let you in the lounge. Don't get too excited though I wasn't that impressed, but they do have free drinks and snacks.
I was going to tell you not to book weekends as you only get coffee and biscuits, but as you can only go weekdays I'm sure you'll be well fed. This has got to be one of the best offers I've seen in awhile, those tickets are worth so much money! I mean, free first class rail tickets where the only qualication is that you've had to be on a plane recently - it doesn't get much better.
Hope you all have good trips