Recommend a router?

[big-all]

no problem! what are bearing guided cutters?

as the name suggests the bearing follows the wood and guids the cutter where to cut
if you dont have a bearing you need a guide fence or baton to guide the router and cutter

you could use this cutter for your groove working from the side [face off the door]
http://www.screwfix.com/app/sfd/cat/pro.jsp?cId=A338074&ts=16159&id=60536

in your case because you would be working from a different face you adjust the depth by changing the bearing[supplied]
you make the groove wider by plunging the router deeper but the maximum would be around 23 mm[1/3 shank =10mm +cutter13mm= 23mm] from the base plate as the router
the cutter should be 2/3 the shank into the collet[chuck] but you could pinch an extra 5mm if you take small cuts and don't load up the cutter to much

the bearing [wheel ]runs on the wood and guids the cutter

 

[kaseryn]

Thanks for that big-all. I think the best thing will be to just get hold of the router and familiarise myself with its workings. Never used one before but i can see a lot of ways it will come in handy