Hey Hun, my little girl is nearly 7months and we live in Lincoln. We go to a surestart group which is based at the Lincoln North Childrens centre but I think Harry will be a bit old for this group as its for smaller babies who aren't walking etc but they do other groups for older babies. All the groups are free, this is a link to the contact details you can just give them a call and ask them what they have which would be suitable for your boy the staff are really helpful. Or you could use the site to see if there is a centre nearer to you?
http://www.surestart.gov.uk/surestartservices/settings/fundedsettings/index.cfm?region=EM&auth=62&prog=3732
I am also thinking of taking Lily to baby signing next week as we are finishing our swimming course today.
http://www.tinytalk.co.uk/baby-signing-classes/baby-signing-lincoln-gilmore.htm
Hope you find something to do with you little boy!