Wheel size.

[gedphones]

Hi everyone. First off I'm a total noob at this cycling lark now so please be gentle with me. First a wee bit of background. I'm getting on a bit (38☺) and have played 5 a sides for enjoyment and keeping a moderate level of fitness for the last 15 years. Now, my right knee feels as if one wrong twist or turn or a mistimed tackle and I'd be out of commission for about 6 months. This isn't an option as I love golfing too much and also.couldn't afford the time off work. So I thought why not cycling. My brother and a few of his buddies swear by it for fun and fitness.
Anyway back to the matter in hand. I bought a Carrara Vulcan from Gumtree. The guy I got it from had kitted it out with mud guards,lights, a padlock and chain that could tether a cruise ship and other odds and ends. He had all the receipts and spent over £500 on it. Also it was only 4 weeks old so I could still take it to halfords for its first service/check. Anyway, it feels good to ride and is comfortable apart from one thing. When standing with my feet on the ground the crossbar is a little bit closer to my crotch for comfort. Today I took it for its first check at halfords and mentioned this to the mechanic. He looked at my position etc on the bike and said this is the size of frame he would have recommended and my position on the saddle was perfect. This put my mind at rest a bit as he seemed a genuine guy. Anyway I was wondering, as the bike comes with 27.5 inch wheels would getting some 26 inch ones help my cause. Would they affect the handling and would they affect the look of the bike negatively.
Cheers folks.

[G]

It shouldn't really be an issue - if you miss your footing or slip off roading, you're in that world of pain anyway. If you don't, it's not an issue.

Using an old adult sized (as a teenager) stermy archer that would suddenly and randomly go in to neutral when standing up to pedal, I got used to staying ON the pedals pretty quickly!

27.5" is the new 'in thing' - presumably for a reason, so I'd stick with them personally.
(Saying that, I bought a 26" this year, but only because it was VERY good value thanks to everyone going for 27.5").

[BumpingUglys]

Not sure if the handling would change too much but the gearing would certainly be lower than intended (assuming you kept the same rear cassette) due to the smaller wheels. The bike would no doubt look weird also with excessive clearances especially on the front end, mine looks odd just with low profile tyres on...

The bike sounds like it's for road use, so in that case I wouldn't worry too much about the top tube clearance, you'll be on the pedals 99% of the time and the height of the tube won't make a blind bit of difference. Start messing about with it and you'll end up spending a chunk of cash on kit in order to make your bike perform worse and look ugly.